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Carbon Transformation Induced by High Energy Excimer Treatment. MATERIALS 2022; 15:ma15134614. [PMID: 35806736 PMCID: PMC9267606 DOI: 10.3390/ma15134614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 01/09/2023]
Abstract
The main aim of this study was to describe the treatment of carbon sheet with a high-energy excimer laser. The excimer modification changed the surface chemistry and morphology of carbon. The appearance of specific carbon forms and modifications have been detected due to exposure to laser beam fluencies up to 8 J cm−2. High fluence optics was used for dramatic changes in the carbon layer with the possibility of Q-carbon formation; a specific amorphous carbon phase was detected with Raman spectroscopy. The changes in morphology were determined with atomic force microscopy and confirmed with scanning electron microscopy, where the partial formation of the Q-carbon phase was detected. Energy dispersive spectroscopy (EDS) was applied for a detailed study of surface chemistry. The particular shift of functional groups induced on laser-treated areas was determined by X-ray photoelectron spectroscopy. For the first time, high-dose laser exposure successfully induced a specific amorphous carbon phase.
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Hashemi H, Alvani A, Aghamirsalim M, Miraftab M, Asgari S. Comparison of transepithelial and conventional photorefractive keratectomy in myopic and myopic astigmatism patients: a randomized contralateral trial. BMC Ophthalmol 2022; 22:68. [PMID: 35148689 PMCID: PMC8832736 DOI: 10.1186/s12886-022-02293-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 02/02/2022] [Indexed: 11/10/2022] Open
Abstract
Background To assess transepithelial photorefractive keratectomy (tPRK) in terms of corneal epithelial healing rate, postoperative pain, postoperative discomfort, and visual and refraction outcomes compared to mechanical epithelial debridement PRK (mPRK) and alcohol-assisted PRK (aaPRK). Methods In this double-masked, randomized clinical trial, thirty-nine patients underwent tPRK in one eye and mPRK in the fellow eye (arm A), and 33 patients underwent tPRK in one eye and aaPRK in the contralateral eye (arm B). All surgical procedures were done using the Schwind Amaris excimer laser. The area of corneal epithelial defect in all eyes was captured and analyzed using ImageJ software. Results Mean epithelial healing time was respectively 3.74 ± 0.82 and 3.59 ± 0.79 days in tPRK versus mPRK (P = 0.21) in arm A, and 3.67 ± 0.92 and 3.67 ± 0.74 days in tPRK versus aaPRK (P = 1.00) in arm B. Accounting for the initial corneal epithelial defect area, the epithelial healing rate was faster in conventional PRK groups compared to tPRK (both P<0.001) in both arms. However, there was no significant difference in safety, efficacy, spherical equivalent refractive accuracy, or corneal haze development between tPRK and conventional PRK groups (all P > 0.05). Conclusions All three methods are effective in terms of visual and refractive outcomes. However, although time to complete re-epithelialization was similar with the three methods, the epithelial healing rate was faster in conventional PRK considering the initial corneal epithelial defect area, and the patients experienced less pain and discomfort in the first postoperative day. Trial registration IRCT, IRCT20200317046804N1. Retrospectively registered 5 May 2020.
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Affiliation(s)
- Hassan Hashemi
- Noor Ophthalmology Research Center, Noor Eye Hospital, 96, Esfandiar Blvd, Valiasr St, Tehran, Tehran, 1968653111, Iran
| | - Azam Alvani
- Noor Ophthalmology Research Center, Noor Eye Hospital, 96, Esfandiar Blvd, Valiasr St, Tehran, Tehran, 1968653111, Iran.
| | | | - Mohammad Miraftab
- Noor Ophthalmology Research Center, Noor Eye Hospital, 96, Esfandiar Blvd, Valiasr St, Tehran, Tehran, 1968653111, Iran
| | - Soheila Asgari
- Noor Ophthalmology Research Center, Noor Eye Hospital, 96, Esfandiar Blvd, Valiasr St, Tehran, Tehran, 1968653111, Iran
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Langrová H, Hejcmanová D, Peregrin J. Visual Functions After Photorefractive Keratectomy. ACTA MEDICA (HRADEC KRÁLOVÉ) 2020. [DOI: 10.14712/18059694.2020.43] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
1. 45 myopes (-3.0 to -6.0 D) were examined before and 1 and 6 months after photorefractive keratectomy (PRK). Visual acuity (VA) was tested using Snellen and logMAR charts. Contrast sensitivity (CS) was measured using a computerized system. 2. Preoperative best corrected VA (BCVA) in myopes was significantly lower in comparison with a control group using logMAR charts only. A reduction of BCVA by both methods at 1. month and its return after 6 months nearly to original values was noted. 3. Significantly lower values of CS were found in patients before PRK compared to the control group. After 1 and 6 months stayed the values on preoperative level.
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Carones F, Brancato R, Morico A, Venturi E, Gobbi PG. Compound Myopic Astigmatism Correction using a Mask In-the-Rail Excimer Laser Delivery System. Preliminary Results. Eur J Ophthalmol 2018; 6:221-33. [PMID: 8908425 DOI: 10.1177/112067219600600301] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The latest development in the erodible mask technology is an excimer laser containing the mask in the laser optical pathway. This paper reports the results of the first human series of consecutive treatments performed for the correction of compound myopic astigmatism. METHODS We have treated 83 eyes. Spherical equivalent attempted correction ranged between -1.75 and -11.75 D (mean -7.07+/- 2.45 D), astigmatic attempted correction ranged between -1.00 and -5.00 D (mean -2.42+/- 1.02 D). The sphere correction was made by diaphragm using a multi-zone software with three ablation zones: 100% of the total attempted correction for the central 5.0 mm zone, 70% for the second 6.0 mm zone, 30% for the outer 6.5 mm zone. Cylinder correction was made sequentially after myopic correction using the appropriate mask. RESULTS One month after treatment, mean refractive error was + 1.07 +/- 1.24 D (range + 4.50/-1.75 D) for spherical equivalent, and -0.49 +/- 0.57 D (range + 0.75/-2.00 D) for astigmatism. Forty-eight eyes (57.8%) had uncorrected visual acuity of 20/40 or better. At six months, mean refractive error was +0.42 +/- 0.97 D (range + 3.75/-1.00 D) for spherical equivalent, and -0.44 +/- 0.51 D (range +0.25/-3.00 D) for astigmatism. Vector analysis showed that 57 eyes (68.7%) had 5 or less degrees rotation. Seventy-two (86.7%) and 54 eyes (65.1%) had uncorrected visual acuity equal or better than 20/40 and 20/25 respectively. One eye (1.2%) showed a best corrected visual acuity loss of more than one line, but 8 eyes (9.6%) had a gain of more than one line. One-year results on a smaller series (33 eyes) overlap with the six-month results. CONCLUSIONS The mask in-the-rail excimer laser delivery system appears to be effective and predictable in the correction of compound myopic astigmatism. We observed no significant regression of the astigmatic correction over time. Longer follow-up on larger series is necessary to draw final conclusions.
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Affiliation(s)
- F Carones
- Department of Ophthalmology and Visual Sciences, Scientific Institute San Raffaele Hospital, University of Milano, Italy
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Brancato R, Carones F, Morico A, Venturi E, Vigo L, Spinelli A, Gobbi PG. Hyperopia Correction Using an Erodible Mask Excimer Laser Delivery System Coupled to an Axicon: Preliminary Results. Eur J Ophthalmol 2018; 7:203-10. [PMID: 9352271 DOI: 10.1177/112067219700700301] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Purpose. This paper presents the results of the first human trial on the correction of hyperopia using an erodible mask excimer laser delivery system coupled to an axicon. Methods. We treated 17 eyes of 17 patients (age range 34–62 years) for the correction of +3.21 ± 1.04 D (range +1.00 to +4.00 D). The hyperopic correction was made using an erodible mask inserted on the laser optical pathway, to produce a circular ablation measuring 6.5 mm in diameter. An axicon was then used to create a blend transition zone from 6.5 mm up to 9.4 mm in diameter. Eyes were evaluated at one, three and six months after surgery. Results. Reepithelization was always observed by the fifth postoperative day, despite the large area of deepithelization (diameter 9.5 mm). Mean refractive error one month after treatment was −2.44 ± 1.59 D (range 0.00 to −6.50 D). Five eyes (29.4%) had a best corrected visual acuity loss more than two to three lines; all eyes showed mild annular haze not involving the central part of the cornea. Six months after treatment, mean refractive error was −0.88 ± 0.99 D (range +0.50 to −3.00 D). Compared to preoperative status, 13 eyes (76.5%) showed an improvement in uncorrected distance visual acuity (1–8 lines), and 14 eyes (82.4%) showed an improvement in uncorrected vision at reading distance (3–7 lines). Two eyes (11.7%) showed a best corrected visual acuity loss of two of three lines. Conclusions. These preliminary results indicate this approach is effective in reducing hyperopia, while its predictability has still to be proved in a larger treatment group with longer follow-up. A cautious approach to this technique is still advisable, especially for higher hyperopic corrections, in view of the large best corrected visual acuity loss seen in two eyes at six months.
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Affiliation(s)
- R Brancato
- Department of Ophthalmology and Visual Sciences, Scientific Institute San Raffaele Hospital, University of Milano, Italy
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Lohmann CP, Patmore A, O'Brart D, Reischl U, Winkler Mohrenfels C, Marshall J. Regression and wound Healing after Excimer Laser Prk: A Histopathological Study on Human Corneas. Eur J Ophthalmol 2018; 7:130-8. [PMID: 9243215 DOI: 10.1177/112067219700700202] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The results of excimer laser PRK are promising as more than 80% of eyes with up to -6.0 diopters of attempted correction have refractive results within 1.0 diopter of emmetropia. However, throughout the dioptric range some unexpected results have been observed with individual patients showing an aggressive wound healing response with excessive myopic regression and severe corneal haze. Unfortunately, only limited data are available about the cellular and extracellular responses in human corneas after PRK and this information is important to establish adequate postoperative pharmaceutical treatment. METHODS We made a histopathological and immunohistochemical study on 20 human corneal samples from patients with severe corneal haze and myopic regression. The indirect immunofluorescence method was used for demonstration of collagen types I, III, IV laminin, chondroitin sulphate, dermatan sulphate, and keratin. RESULTS All corneal specimens showed a hyperplastic epithelium. Histologically, most samples (16/20) showed mainly a loose lamination of extracellular material which could be identified as collagen type IV. The remaining four samples had newly synthesised collagen type III. CONCLUSIONS Our histopathological results indicate that corneal wound healing after excimer laser PRK varies among individuals. In some people epithelial basement proteins, such as collagen type IV, are the main wound healing products, whereas in others mainly collagen type III is found postoperatively, which does not effect the synthesis of collagen type IV. This suggests the need for individually-tailored postoperative pharmaceutical treatment regimens.
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Affiliation(s)
- C P Lohmann
- University Eye Clinic, University of Regensburg, Germany
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Carones F, Brancato R, Venturi E, Vigo L. The Human Corneal Endothelium after Myopic Excimer Laser Photorefractive Keratectomy. Immediate to One-Month Follow-Up. Eur J Ophthalmol 2018; 5:204-13. [PMID: 8963155 DOI: 10.1177/112067219500500402] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To assess whether excimer laser photorefractive keratectomy for myopia (PRK) induced any changes in the human corneal endothelium in the immediate postoperative period and up to one month after surgery. METHODS No-contact wide-field specular biomicroscopy of the central corneal endothelium was performed on 56 eyes of 56 patients (age 20-54 years, mean 31.3) who underwent photorefractive keratectomy for the correction of myopia ranging between 1.25 and 12.50 D (5.71 +/- 2.96 D, mean +/- SD). Images of the endothelium were obtained using the NonCon Robo endothelial biomicroscope (Konan, Hyogo, Japan), and processed to calculate the mean cell density (MCD), the coefficient of variation of cell area (CV), and the percentage of hexagonal cells (Hex%). Eyes were evaluated immediately before (preop) and after surgery (day 0), on the first two postoperative days (days 1 and 2), and after one month. RESULTS MCD was 2645 +/- 344 cells/mm2 at preop, 2609 +/- 293 cells/mm2 on day 0, 2681 +/- 320 cells/mm2 on day 1, 2629 +/- 305 cells/mm2 on day 2, and 2709 +/- 308 cells/mm2 at one month; a significant difference was found only comparing preoperative to one month data (p = 0.009). CV was 31.6 +/- 4.7 at preop, 39 +/- 7.1 on day 0 (p = 0.000001), 37.1 +/- 7.8 on day 1 (p = 0.00005), 43.4 +/- 13.1 on day 2 (p = 0.000001), and 34.7 +/- 5.8 on one month (p = 0.0006). Hex% was 61.9 +/- 7.1 at preop, 58 +/- 7.3 on day 0 (p = 0.002), 58.5 +/- 8.5 on day 1 (p = 0.015), 57.1 +/- 8.5 on day 2 (p = 0.00004), and 59.3 +/- 7.5 at one month (p = 0.002). No correlations were found between ablation depth and endothelial changes. CONCLUSIONS Endothelial cell density was not reduced by PRK in the immediate postoperative period. Changes in morphological indices like CV and Hex% indicate that the photoablation causes some kind of damage to the endothelial cells.
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Affiliation(s)
- F Carones
- Department of Ophthalmology and Visual Sciences, Scientific Institute San Raffaele Hospital, University of Milano, Italy
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Tasindi E, Talu H, Ciftci F, Acar S. Excimer Laser Photorefractive Keratectomy (Prk) in Myopic Astigmatism. Eur J Ophthalmol 2018; 6:121-4. [PMID: 8823582 DOI: 10.1177/112067219600600204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
UNLABELLED To assess the visual and refractive results of excimer laser photorefractive keratectomy (PRK) in myopic astigmatism. METHODS Excimer laser PRK was performed using an Aesculap Meditec MEL 60 laser in 46 myopic astigmatic eyes. Preoperative corneal astigmatism was -1.50 D. (+/- 0.50) in 7 eyes (15.2%); -2.50 D. (+/- 0.50 in 14 eyes (30.5%); -3.50 D. (+/- 0.50) in 13 eyes (28.3%); -4.50 D. (+/- 0.50) in 8 eyes (17.4%); and -5.50 D. (+/- 0.50) in 4 eyes (8.6%). Mean preoperative cylinder was -3.50 D. (+/- 2.50). Mean preoperative sphere was -4.50 D. (+/- 2.25). Pre and post-operative visual acuity, refraction, keratometer readings, corneal topography, intraocular pressure, and slit lamp findings were recorded. RESULTS By one year of follow-up, postoperative cylinder was between +0.50 and -0.50 D. in 31 eyes (67.4%); between -0.50 and -1.50 D. in 11 eyes (23.9%); between -1.50 and -2.50 D. in 4 eyes (8.7%). Mean post-operative cylinder was -1.21 D. (+/- 1.70). Mean postoperative sphere was -1.09 D. (+/- 1.25). Myopic and astigmatic improvement was achieved in each patient (100%). Topography analysis showed 69.4% were within 0.5 mm, 96.8% within 1 mm, 97.8% within 1.5 mm of centration; 55% of the patients achieved uncorrected visual acuity of 10/10 (Snellen). One patient (2.2%) lost one line of best corrected vision due to decentration and change of axis. CONCLUSION These preliminary results of myopic astigmatic excimer laser PRK procedures compare favorably in efficiency and safety with reports of PRK for myopia.
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Affiliation(s)
- E Tasindi
- Veni Vidi Eye Health Center, Gulhane Military Academy, Ophthalmology Department, Istanbul, Turkey
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Refractive Errors & Refractive Surgery Preferred Practice Pattern®. Ophthalmology 2018; 125:P1-P104. [DOI: 10.1016/j.ophtha.2017.10.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/02/2017] [Indexed: 11/19/2022] Open
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Comparison of visual and refractive results after transepithelial and mechanical photorefractive keratectomy in myopia. Int Ophthalmol 2017; 38:627-633. [DOI: 10.1007/s10792-017-0501-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/13/2017] [Indexed: 12/14/2022]
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Slade SG, Doane JF. Excimer Laser in Situ Keratomileusis. Semin Ophthalmol 2009. [DOI: 10.3109/08820539609063819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Rajpal RK, Cooperman BB. Clinical Results of Photorefractive Keratectomy in Low to Moderate Myopia and Astigmatism. Semin Ophthalmol 2009. [DOI: 10.3109/08820539609063816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Nassaralla BA, McLeod SD, Nassaralla JJ. Prophylactic Mitomycin C to Inhibit Corneal Haze After Photorefractive Keratectomy for Residual Myopia Following Radial Keratotomy. J Refract Surg 2007; 23:226-32. [PMID: 17385287 DOI: 10.3928/1081-597x-20070301-04] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the efficacy and safety of mitomycin C (MMC) 0.02% in inhibiting haze formation after excimer laser photorefractive keratectomy (PRK) for residual myopia following radial keratotomy (RK). METHODS A prospective, nonrandomized, noncomparative interventional case series was conducted of 22 eyes (14 patients) with residual myopia after RK performed at a single institution. All eyes were treated with PRK and a single intraoperative topical application of MMC 0.02% solution for 2 minutes using a soaked cellulose sponge placed over the ablated area. Refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and slit-lamp evidence of cotneal opacity (haze) were evaluated over 12 months. RESULTS Twelve months postoperatively, 3 eyes showed grade 1 haze, and 2 eyes showed grade 0.5 haze. Twelve months postoperatively, 2 (9%) eyes had UCVA > or = 20/20. No eye before and 17 (77%) eyes after treatment had UCVA > or = 20/40, and no eye before and 9 eyes (40.9%) after treatment had UCVA > or = 20/25. Best spectacle-corrected visual acuity was > or = 20/40 in all (100%) eyes and 21 (95%) eyes before and after treatment, respectively, and > or = 20/25 in 12 (54.5%) eyes before and after treatment. One (4.5%) eye lost 1 line of BSCVA. Mean spherical equivalent refraction achieved was -0.18 diopters (D) (range: -0.75 to +0.50 D) compared to -2.72 D (range: -1.50 to -4.00 D) before treatment. Twelve months after treatment, 19 (85.5%) eyes had a refractive outcome within +/- 0.50 D. CONCLUSIONS A single intraoperative application of MMC 0.02% for 2 minutes appears to be effective in preventing subepithelial haze after PRK for residual myopia in patients with undercorrection or regression following RK.
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Affiliation(s)
- Belquiz A Nassaralla
- Department of Cornea and Refractive Surgery, Goiania Eye Institute, Goiania, GO, Brazil.
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Abstract
Mitomycin C is a chemotherapeutic agent that acts by inhibiting DNA synthesis. Its use and application in ophthalmology has been increasing in recent years because of its modulatory effects on wound healing. Current applications include pterygium surgery, glaucoma surgery, corneal refractive surgery, cicatricial eye disease, conjunctival neoplasia and allergic eye disease. Although it has been used successfully in these conditions, it has also been associated with significant complications. This article reviews the current trends and uses of mitomycin C in the eye and its reported complications.
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Affiliation(s)
- Ali A Mearza
- Emmetropia Mediterranean Eye Institute, Parodos Anapoleos 7, Heraklion, Crete GR 71201, Greece
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Munnerlyn CR, Arnoldussen ME, Munnerlyn AL, Logan BA. Theory concerning the ablation of corneal tissue with large-area, 193-nm excimer laser beams. JOURNAL OF BIOMEDICAL OPTICS 2006; 11:064032. [PMID: 17212555 DOI: 10.1117/1.2399091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Excimer laser beams (193 nm) of uniform fluence were studied to find out why they produce corneal ablations deeper at the edge than the center. Ablation depth profiles were taken of porcine corneas, including five dehydrated samples. Hydrated corneas and polymethyl methacrylate were ablated with and without central masks. Ablation plumes were photographed. Hydrated porcine corneas showed patterns of central underablation. As the incident beam increased, the crater exhibited increasingly shallower central ablation while maintaining nearly constant depth at the edges. Dehydrated corneas did not vary significantly. Masks did not alter the depth or shape of craters near ablation edges, but depth adjacent to the images of the masks was more than twice that with no mask. Depth adjacent to the mask image was nearly the same as at the edge of the zone. The rate of change in depth with position was nearly equal in both areas. Maximum plume density was centered over the entire ablation with and without the mask. Redeposition of plume particles is not the major cause of central underablation. Propagating transverse energy from the absorption of photons by peptide bonds increases pressure on excited components within the irradiated area, increasing recombination, which raises the ablation threshold.
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Affiliation(s)
- Charles R Munnerlyn
- Advanced Medical Optics, Incorporated, 3400 Central Expressway, Santa Clara, California 95050, USA
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Argento C, Cosentino MJ, Ganly M. Comparison of Laser Epithelial Keratomileusis With and Without the Use of Mitomycin C. J Refract Surg 2006; 22:782-6. [PMID: 17061715 DOI: 10.3928/1081-597x-20061001-08] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To analyze the results of prophylactic intraoperative use of mitomycin C (MMC) in laser epithelial keratomileusis (LASEK). METHODS A retrospective analysis of 30 LASEK cases that received MMC 0.02% intraoperatively (MMC group) was performed and compared to the results obtained in 28 LASEK cases not receiving MMC (no MMC group). Mitomycin C was placed in contact with the ablation zone for 75 seconds with an imbibed microsponge. Both groups received postoperative fluorometholone for 3 months. Preoperative spherical equivalent refraction was -5.72 +/- 2.82 diopters (D) in the MMC group and -5.81 +/- 2.74 D in the no MMC group. Best spectacle-corrected visual acuity was 0.88 +/- 0.12 in the MMC group and 0.88 +/- 0.13 in the no MMC group. RESULTS Spherical equivalent refraction at 6 months postoperatively was +0.11 +/- 0.13 D in the MMC group and +0.09 +/- 0.37 D in the no MMC group. Best spectacle-corrected visual acuity was 0.90 +/- 0.13 in the MMC group and 0.88 +/- 0.13 in the no MMC group. Uncorrected visual acuity (UCVA) > or = 20/40 was obtained in 93.3% of cases in the MMC group and in 89.3% of cases in the no MMC group; UCVA > or = 20/25 was achieved in 76.6% of cases in the MMC group and in 71.4% of cases in the no MMC group. Haze incidence for the MMC group was: trace: 0%, Grades I: 0%, II: 0%, III 0%, IV: 0%, and for the no MMC group: trace: 17.9%, Grades I: 3.6%, II: 0%, III: 0%, IV: 0%. A statistically significant difference (P<.001) was noted in haze intensity between the MMC group and no MMC group. CONCLUSIONS Prophylactic use of intraoperative MMC in LASEK significantly decreases haze incidence.
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Argento C, Cosentino MJ. Laser in situ keratomileusis: ablation on the flap and stromal bed in a primary treatment. J Cataract Refract Surg 2006; 32:590-4. [PMID: 16698477 DOI: 10.1016/j.jcrs.2006.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 05/13/2005] [Indexed: 11/27/2022]
Abstract
PURPOSE To analyze outcomes of laser in situ keratomileusis (LASIK) performed on the flap and on the stromal bed at the same time in a primary treatment. SETTING Instituto de la Visión, Buenos Aires, Argentina. METHODS Twenty-two cases (13 female, 9 male) were studied retrospectively; the mean age of the patients was 33.15 years +/- 10.44 (SD). Inclusion criteria were low pachymetry or topographic asymmetry. Twenty cases (90.9%) presented with low pachymetry (512.2 +/- 21.40 mum), and 2 cases (9.1%) presented with topographic asymmetry (inferior-superior difference more than 1.5 diopters [D]). Ablation was performed on the flap from the back and on the bed. The flap was made using the Technolas Hansatome microkeratome and the ablation by the Technolas 217z excimer laser (both by Bausch & Lomb). Preoperatively, the spherical equivalent (SE) was -5.61 +/- 1.72 D, the cylinder was -1.78 +/- 1.24 D, and the best spectacle-corrected visual acuity (BSCVA) was 0.77 +/- 0.19. Difficulties and complications of the technique, efficacy and safety index, and aberrations were analyzed. RESULTS According to the surgical plan and our nomogram, diopters corrected on the flap were -1.73 +/- 1.08 and on the bed were -4.77 +/- 1.89. The mean follow-up was 8.28 +/- 2.19 months. At 6 months, the SE was -0.21 +/- 0.39, vectorial change was 1.69 +/- 0.74, and the BSCVA was 0.77 +/- 0.20. Postoperatively, no eye had an increase in refractive astigmatism. Uncorrected visual acuity was 20/40 or better in all cases (100%) and 20/25 or better in 13 cases (59.1%). Regarding gained and lost lines of BSCVA, 54.5% conserved the lines, 18.2% lost 1 line, 9.1% gained 1 line, and 18.2% gained 2 lines. CONCLUSIONS Simultaneous ablation on the flap and on the bed in cases of low pachymetry or topographical asymmetry was predictable, effective, and safe.
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Affiliation(s)
- Carlos Argento
- Instituto de la Visión, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
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O'Brart DPS, Al-Attar M, Hussein B, Angunawela R, Marshall J. Laser Subepithelial Keratomileusis for the Correction of High Myopia With the Schwind ESIRIS Scanning Spot Laser. J Refract Surg 2006; 22:253-62. [PMID: 16602314 DOI: 10.3928/1081-597x-20060301-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the efficacy of laser subepithelial keratomileusis (LASEK) for the correction of high myopia with the Schwind ESIRIS scanning spot laser (Schwind eye-tech-solutions Gmbh & Co, Kleinostheim, Germany). METHODS Fifty-one patients (76 eyes) were treated with a mean preoperative spherical equivalent refraction of -7.55 diopters (D) (range: -6.0 to -10.75 D). All eyes received a LASEK technique using 15% alcohol with a 20-second application. RESULTS An intact epithelial flap was obtained in 73 (96%) eyes. At 1 week, uncorrected visual acuity (UCVA) was > or =20/30 in 53 (70%) eyes and > or =20/60 in all eyes. At 6 months (n=76), the mean SE was +0.08 D (range: -1.00 to +1.875 D) with 73 (96%) eyes within +/-1.0 D of the intended correction and 60 (79%) eyes within +/-0.5 D. At 12 months (n=46), the mean SE was -0.07 D (range: -1.375 to +2.0 D) with 44 (96%) eyes within +/-1.0 D of the intended correction and 37 (80%) eyes within +/-0.5 D. Myopic cylindrical corrections were attempted in 68 eyes (range: -0.25 to -4.25 D) with vector analysis demonstrating a mean 85% correction. At last follow-up, UCVA was > or =20/20 in 47 (62%) eyes, > or =20/25 in 63 (83%) eyes, and > or =20/40 in 75 (99%) eyes. Three (4%) eyes gained two lines of Snellen decimal equivalent best spectacle-corrected visual acuity compared to preoperative levels, 68 (89%) eyes showed no change or gained one line, and 5 (7%) eyes lost one line. None lost more than one line. Only 2 (3%) eyes at 6 to 12 months had more than +1 axial corneal haze and 50 (66%) showed no evidence of haze on slit-lamp examination. CONCLUSIONS Laser subepithelial keratomileusis for myopia up to -11.00 D with the Schwind ESIRIS laser provides good refractive and visual outcomes, with acceptable visual recovery and minimal complications.
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Affiliation(s)
- David P S O'Brart
- Department of Ophthalmology, St Thomas' Hospital, London, United Kingdom.
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Bergmanson JP, Farmer EJ. A return to primitive practice? Radial keratotomy revisited. Cont Lens Anterior Eye 2005; 22:2-10. [PMID: 16303397 DOI: 10.1016/s1367-0484(99)80024-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recently, a refractive surgeon was quoted in the national and professional press as proposing that radial keratotomy (RK) is to be preferred over laser procedures, such as photorefractive keratectomy (PRK) and laser assisted in situ keratomileusis (LASIK). The rationale for this public recommendation was that the RK procedure achieves better visual results and fewer complications than the laser procedures. Peer reviewed literature on these refractive procedures was surveyed to establish the validity of such a statement and it was found that current data do not support the notion that RK results in better visual outcomes than PRK and LASIK The true incidence of complications is difficult to establish. However, when the post procedure chronic effects are compared between RK, PRK and LA SIK, it becomes apparent that the post-RK patient pays the highest price, by a large margin, in visual quality impairment and corneal health. Although the visual acuity outcomes for low to moderate myopes, when corrected by any of the three refractive procedures considered here, are not dramatically different, we concluded that RK is not the preferred methodology because of its associated chronic visual and corneal health complications.
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O'Brart DPS, Patsoura E, Jaycock P, Rajan M, Marshall J. Excimer laser photorefractive keratectomy for hyperopia: 7.5-year follow-up. J Cataract Refract Surg 2005; 31:1104-13. [PMID: 16039483 DOI: 10.1016/j.jcrs.2004.10.051] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2004] [Indexed: 11/21/2022]
Abstract
PURPOSE To report the results of a long-term prospective study to evaluate refractive stability and safety of hyperopic photorefractive keratectomy (H-PRK). SETTING Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. METHODS Twenty-one patients (49%) (40 eyes) of cohort of 43 patients who participated in 1 of the first clinical trials of H-PRK were assessed at a mean follow-up of 90.7 months (range 62 to 106 months). The H-PRK was performed using a Summit Technology Apex Plus Excimer laser (Summit Technology, Inc.). The mean preoperative spherical equivalent refraction (SEQ) was +4.70 diopters (D) (range +2.00 to +7.50 D). Patients were allocated to 1 of 4 treatment groups based on their preoperative refraction and received 1 of the following spherical corrections: +1.50 D, +3.00 D, +4.50 D, or +6.00 D. RESULTS At 7.5 years, the refractive correction remained stable with a mean difference in SEQ between 1 year and 7.5 years of +0.28 D. The mean manifest SEQ was +0.83 D (range +5.00 to -3.00 D). Sixty-seven percent of eyes having corrections of +1.50 D and +3.00 D were within +/-1.00 D of the predicted correction. Predictability was poorer with +4.50 D and +6.00 D corrections, with 40% of eyes within +/-1.00 D of that expected. An improvement in uncorrected near acuity was achieved in 35 eyes (87.5%), and 35 eyes (87.5%) showed an improvement in uncorrected distance acuity from preoperative levels. Best spectacle-corrected visual acuity (BSCVA) was unchanged or improved from preoperative values in 25 eyes (62.5%). Three eyes (8%) lost 2 lines of Snellen BSCVA, which in 2 cases was attributable to cataract formation. A peripheral ring of haze, 6.5 mm in diameter, appeared in most eyes. Its intensity was greatest at 6 months and then diminished with time. In 10 eyes (25%), remnants of the haze ring were evident at 7.5 years and subepithelial iron rings, 6.5 mm in diameter were evident in 26 eyes (70%). No patient complained of night-vision problems and no eye developed ectasia. CONCLUSIONS In H-PRK, refractive stability achieved at 1 year was maintained up to 7.5 years with no evidence of hyperopic shift, diurnal fluctuation, or late regression. Peripheral corneal haze decreased with time but was still evident in a number of eyes at the last follow-up visit.
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Affiliation(s)
- David P S O'Brart
- Department of Ophthalmology, St. Thomas' Hospital, London SE1 7EH, UK.
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Gambato C, Ghirlando A, Moretto E, Busato F, Midena E. Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes. Ophthalmology 2005; 112:208-18; discussion 219. [PMID: 15691552 DOI: 10.1016/j.ophtha.2004.07.035] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 07/28/2004] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes. DESIGN Prospective, double-masked, randomized clinical trial. PARTICIPANTS Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia. METHODS In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months). MAIN OUTCOME MEASURES Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH. RESULTS Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively). CONCLUSION Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
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Affiliation(s)
- Catia Gambato
- Refractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy
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Jaycock PD, O'Brart DPS, Rajan MS, Marshall J. 5-year follow-up of LASIK for hyperopia. Ophthalmology 2005; 112:191-9. [PMID: 15691550 DOI: 10.1016/j.ophtha.2004.09.017] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Accepted: 09/02/2004] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To assess the long-term efficacy and stability of LASIK for hyperopia (+0.75 to +7.00 diopters [D]). DESIGN Retrospective follow-up study of a previous phase III multicenter clinical trial (unpublished data). PARTICIPANTS Patients who had been treated for hyperopia (33 individuals, 47 eyes) attended follow-up 5 years after surgery. The preoperative mean spherical equivalent at the spectacle plane was +3.58 D (range, +0.75 to 7.00 D), and the attempted mean spherical correction at the corneal plane was +3.18 D (range, +1.00 to +6.00 D). INTERVENTION Treatments were performed using a Moria LSK One microkeratome and a Summit Technology SVS Apex Plus excimer laser fitted with an Axicon. MAIN OUTCOME MEASURES Manifest refraction, uncorrected visual acuity, best spectacle-corrected visual acuity, corneal transparency, complications, and patient satisfaction were recorded. RESULTS At 5 years, for treatments between +1.00 to +3.00 D, 71.0% of eyes were within +/-1.00 D of the intended correction, and for treatments between +3.5 to +6.0 D, 37.5% of eyes were within +/-1.00 D of intended correction. From 12 to 54 months after surgery for all patients, there was a hyperopic shift of +0.53 D (range, -0.13 to +3.13 D), with 51.1% of eyes experiencing an increase of +0.50 D or more and 27.7% of eyes showing a hyperopic shift of more than +1.00 D. This hyperopic shift was +0.67 D (range, 0 to +1.125 D) for patients younger than 40 years of age and +0.44 D (range, -1.33 to +1.50 D) for patients between 43 and 55 years of age. CONCLUSIONS LASIK was moderately effective for the correction of low degrees of hyperopia. However, there was regression throughout the 5-year follow-up that was greater than would be expected as a result of aging. Long-term stability of hyperopic LASIK refractive corrections, therefore, is uncertain.
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Affiliation(s)
- Philip D Jaycock
- Rayne Institute, Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom
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Abstract
PURPOSE OF REVIEW This study reviews current concepts in laser subepithelial keratectomy (LASEK), variations in LASEK techniques, the role of pharmacology in LASEK, and optimizing outcomes in LASEK. RECENT FINDINGS Recent studies continue to support the use of LASEK over that of LASIK in the correction of refractive error. In addition, the advent of pharmacological/biologic intervention, improved algorithms, and wavefront technology have expanded the armamentarium available to ophthalmologists in the maximization of LASEK outcomes. SUMMARY LASEK offers an excellent profile in terms of both final outcome (uncorrected visual acuity) and safety (best corrected visual acuity). Untoward effects of LASEK are readily prevented/treated with a variety of agents. Postoperative pain can be ameliorated using topical and oral analgesia. Infection can be most effectively addressed with the fourth generation of fluoroquinolones. Haze may be treated or prevented using numerous remedies namely autologous serum, steroids, ascorbic acid, mitomycin-c, and NSAIDS. Wavefront combined with LASEK rather than with LASIK may offer the best refractive outcome.
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Affiliation(s)
- Richard W Yee
- Hermann Eye Center, Department of Ophthalmology and Visual Science, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA.
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Kaya V, Oncel B, Sivrikaya H, Yilmaz OF. Prospective, Paired Comparison of Laser in situ Keratomileusis and Laser Epithelial Keratomileusis for Myopia Less Than -6.00 Diopters. J Refract Surg 2004; 20:223-8. [PMID: 15188898 DOI: 10.3928/1081-597x-20040501-05] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare visual and refractive results, contrast sensitivity, and tear stability after laser in situ keratomileusis (LASIK) in one eye and laser epithelial keratomileusis (LASEK) in the fellow eye for low myopia. METHODS Patients diagnosed with low myopia, with a maximum difference of 1 D between their two eyes, were randomly assigned to receive LASEK on one eye and LASIK on the other eye. A total of 64 eyes of 32 patients with a mean age of 26.83 +/- 5.33 years were included in the study. Preoperative myopia ranged from -1.00 to -6.00 D. Follow-up was 6 to 12 months. Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), Schirmer test results, tear break-up time, corneal asphericity, corneal uniformity index, predicted corneal acuity, and contrast sensitivity values were compared with preoperative values. A Wilcoxon test was used for statistical comparisons and a P-value less than .05 was considered significant. RESULTS At 6 months after surgery, there was no statistically significant difference in UCVA, BSCVA, spherical and cylindrical refractive error, Schirmer test, or tear break-up time between groups. Contrast sensitivity values in the LASIK eyes were lower in comparison to preoperative values, but there was no change in the LASEK group. CONCLUSIONS Based on 6-month results, LASEK for low myopia was safe and effective with predictable results, offered early refractive stability, and may be considered an alternative for LASIK.
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Affiliation(s)
- Vedat Kaya
- Beyoglu Eve Education and Research Hospital, Istanbul, Turkey
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26
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Bilgihan K, Hondur A, Hasanreisoglu B. Laser Subepithelial Keratomileusis for Myopia of -6 to -10 Diopters With Astigmatism With the MEL60 Laser. J Refract Surg 2004; 20:121-6. [PMID: 15072310 DOI: 10.3928/1081-597x-20040301-05] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the efficacy, predictability, and safety of laser subepithelial keratomileusis (LASEK) for treatment of high myopia with astigmatism. METHODS LASEK was performed in 61 eyes of 36 consecutive patients with myopic spherical equivalent refraction of -6.00 to -10.00 D using the Aesculap-Meditec MEL60 excimer laser. Data were collected prospectively with a follow-up of 6 to 17 months. Main outcome measures recorded were UCVA, BSCVA, residual refractive error, corneal haze, and complications. RESULTS Ninety-six percent of eyes achieved 20/40 or better UCVA at 1 month. At 12 months, 64% of eyes achieved 20/20 and 92% achieved 20/40 or better UCVA. Two eyes lost 2 lines of BSCVA at 6 or 12 months. Accuracy of correction was +/- 0.50 D from emmetropia in 82% of eyes, and +/- 1.00 D in 90% at 12 months. No eye showed more than grade 1 haze. Grade 1 haze was observed in three eyes at 12 months. One patient had mild postoperative keratitis, which was successfully treated. CONCLUSIONS LASEK with the Aesculap-Meditec MEL60 excimer laser appeared to be safe, effective, and highly predictable in treating high myopia.
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Affiliation(s)
- Kamil Bilgihan
- Gazi University Medical School, Department of Ophthalmology, Ankara, Turkey.
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27
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Chalita MR, Tekwani NH, Krueger RR. Laser Epithelial Keratomileusis: Outcome of Initial Cases Performed by an Experienced Surgeon. J Refract Surg 2003; 19:412-5. [PMID: 12899471 DOI: 10.3928/1081-597x-20030701-06] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate refractive outcome and objective clinical data, and determine efficacy, predictability, and safety of laser epithelial keratomileusis (LASEK) for myopic treatments. METHODS We performed a retrospective non-comparative single-surgeon case series on the first 20 LASEK procedures (Alcon LADARVision 4000 laser). Mean patient age was 41.2 years (range 21 to 60 yr): 13 men and 7 women. Mean preoperative spherical equivalent refraction was -6.47+/-2.78 D. Corneal haze, uncorrected and spectacle-corrected visual acuity and manifest refraction were evaluated. RESULTS Of 20 eyes studied, 3 were corrected for monovision. In the non-monovision group, 20/40 or better visual acuity was achieved in 94% (16 eyes) at 1 month, 100% (13 eyes) at 3 months, and 91% (10 eyes) at 6 months after LASEK; 20/20 or better was achieved in 12% (2 eyes) at 1 month, 46% (6 eyes) at 3 months, and 45% (5 eyes) at 6 months. Corneal haze at 1 month was grade 0.5 in 35% (7 eyes), 1 in 20% (4 eyes) and 2 in 10% (2 eyes). At 3 months, 62% (12 eyes) had grade 0.5 and 31% (6 eyes) had grade 1. At 6 months, 58% (12 eyes) had grade 0.5, 25% (5 eyes) had grade 1, and 8% (2 eyes) had grade 2. CONCLUSIONS LASEK is a challenging procedure. Creating the epithelial flap is not simple and may have contributed to the high haze incidence in our study.
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Affiliation(s)
- Maria Regina Chalita
- Department of Ophthalmology, The Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Autrata R, Rehurek J. Laser-assisted subepithelial keratectomy for myopia: two-year follow-up. J Cataract Refract Surg 2003; 29:661-8. [PMID: 12686232 DOI: 10.1016/s0886-3350(02)01897-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE To assess and compare the clinical results (efficacy, safety, stability, and postoperative pain or discomfort) of laser-assisted subepithelial keratectomy (LASEK) and conventional photorefractive keratectomy (PRK) for the correction of low to moderate myopia. SETTING Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic. METHODS A prospective comparative study was performed in 184 eyes of 92 patients who had surface excimer ablation for the correction of myopia. The preoperative mean spherical equivalent (MSE) was -4.65 diopters (D) +/- 3.14 (SD) (range -1.75 to -7.50 D). In each patient, LASEK was performed in 1 eye and PRK in the fellow eye by the same surgeon. The first eye treated and the surgical method used in the first eye were randomized. Both procedures were performed with the Nidek EC-5000 excimer laser using the same parameters and nomogram. The postoperative pain level, visual recovery, complications (haze), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and refractive outcome were evaluated and compared. All eyes completed a 24-month follow-up. RESULTS The postoperative MSE was -0.18 +/- 0.53 D in the PRK eyes and -0.33 +/- 0.46 D in the LASEK eyes. At 1 week, the mean UCVA was 0.64 +/- 0.21 and 0.87 +/- 0.23, respectively. No LASEK eye lost a line of BSCVA. There were no statistically significant differences between PRK and LASEK eyes in the safety and efficacy indices at 2 years. The mean pain level was significantly lower on days 1 to 3 in the LASEK eyes (P <.05). The mean corneal haze level was lower in the LASEK eyes (0.21) than in the PRK eyes (0.43) (P <.05). Seventy-nine patients preferred LASEK to PRK. CONCLUSIONS Laser-assisted subepithelial keratectomy provided significantly quicker visual recovery, eliminated post-PRK pain, and reduced the haze level in eyes with low to moderate myopia compared with conventional PRK. It provided good visual and refractive outcomes. There were no serious complications.
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Affiliation(s)
- Rudolf Autrata
- Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic.
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Donnenfeld ED, O'Brien TP, Solomon R, Perry HD, Speaker MG, Wittpenn J. Infectious keratitis after photorefractive keratectomy. Ophthalmology 2003; 110:743-7. [PMID: 12689896 DOI: 10.1016/s0161-6420(02)01936-x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To elucidate risk factors, microbial culture results, and visual outcomes for infectious keratitis after photorefractive keratectomy (PRK). DESIGN Multicenter, retrospective chart review, case report, and literature review. METHODS The records of 12 patients with infectious keratitis after PRK were reviewed. MAIN OUTCOME MEASURES Causative organism, response to medical treatment, and visual outcome. RESULTS Infectious keratitis developed in 13 eyes of 12 patients after PRK. Organisms cultured were Staphylococcus aureus (n = 5), including a bilateral case of methicillin-resistant Staphylococcus aureus; Staphylococcus epidermidis (n = 4); Streptococcus pneumoniae (n = 3); and Streptococcus viridans (n = 1). Four patients manipulated their contact lenses, and 2 patients were exposed to nosocomial organisms while working in a hospital environment. Prophylactic antibiotics used were tobramycin (nine cases), polymyxin B-trimethoprim (three cases), and ciprofloxacin (one case). Final best spectacle-corrected visual acuity ranged from 20/20 to 20/100. CONCLUSIONS Infectious corneal ulceration is a serious potential complication of PRK. Gram-positive organisms are the most common pathogens. Antibiotic prophylaxis should be broad spectrum and should include gram-positive coverage.
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Affiliation(s)
- Eric D Donnenfeld
- Department of Ophthalmology, Nassau University Medical Center, East Meadow, New York, USA
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Abstract
Laser subepithelial keratomileusis (LASEK) is a relatively new refractive surgical technique that purportedly combines the advantages of laser in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). Like LASIK, on the one hand, it employs a "flap" and consequently has the advantages of faster visual recovery, less postoperative pain, reduced stromal haze, and faster epithelial healing than PRK. Like PRK, on the other hand, because the procedure is performed on the anterior cornea, there are virtually no flap- or interface-related complications per se. It may thus be safer for patients who are at an inherently higher risk of developing flap complications, such as those with small palpebral fissures, deep-set eyes, corneal basement membrane dystrophy, and extremely steep or flat corneas. Furthermore, it conserves precious stroma in eyes with thin corneas or high myopia, which otherwise may not qualify for LASIK. It may also be more apropos for patients whose jobs or recreational activities put them at a higher risk of corneal trauma. In a very timely fashion, for reasons discussed below, LASEK may also prove to be superior to LASIK in customized ablations.
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Affiliation(s)
- Mohammad H Dastjerdi
- University of Michigan, W.K. Kellogg Eye Center, Ann Arbor, Michigan 48105, USA.
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31
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Shen EP, Yang CN, Hu FR. Corneal astigmatic change after photorefractive keratectomy and photoastigmatic refractive keratectomy. J Cataract Refract Surg 2002; 28:491-8. [PMID: 11973096 DOI: 10.1016/s0886-3350(01)01157-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To evaluate and compare the efficacy, safety, predictability, and surgically induced astigmatism (SIA) of photorefractive keratectomy (PRK) and photoastigmatic refractive keratectomy (PARK). SETTING Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan. METHODS In this retrospective study, 70 eyes were treated for myopia and 70 eyes were treated for myopic astigmatism. Refraction, corneal topography, slitlamp findings, and visual acuity in the 2 groups at 1, 3, and 6 months were evaluated and compared. Vector analysis was performed to determine the SIA in both groups. RESULTS The mean preoperative spherical equivalent at the glasses plane in the PRK and PARK groups was -6.06 diopters (D) and -7.18 D, respectively. At 6 months, the mean reduction in astigmatism in the PARK group was 61.0%. Predictability was within +/-1.0 D in 85.2% of eyes in the PRK group and 62.5% in the PARK group. An uncorrected visual acuity of 20/40 or better was achieved in 91.8% and 83.9% of eyes, respectively. The mean SIA was 0.64 D in the PRK group, with a general with-the-rule axis shift. The results of vector analysis were more favorable when calculated from refractive values than from Sim-K corneal topography values. The mean astigmatism correction index and index of success calculated from refractive data were 0.75 and 0.38 in the PARK group. The mean magnitude and angle of error were 0.22 +/- 0.52 D and -2.13 +/- 24.41 degrees, respectively. CONCLUSIONS Photorefractive keratectomy and PARK were effective and safe procedures for the correction of myopia and myopic astigmatism. However, SIA occurred with spherical myopic treatments. This small SIA may be a confounding factor in low astigmatic treatments.
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Affiliation(s)
- Elizabeth P Shen
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
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Abstract
PURPOSE To evaluate the results of laser-assisted subepithelial keratectomy (LASEK) for spherical and spherocylindrical myopia. SETTING Indiana Eye Institute, South Bend, Indiana, USA. METHODS In a retrospective noncomparative single-surgeon interventional case series, outcomes in 222 consecutive eyes with myopia ranging from -1.25 to -11.25 diopters (D) and astigmatism up to +2.25 D treated with LASEK using a VISX Star S2 excimer laser were analyzed 4 days, 2 weeks, and 3, 6, and 12 months after surgery. RESULTS The uncorrected visual acuity (UCVA) was 20/40 or better in 84% of eyes at 4 days and in 98% at 2 weeks. At 12 months, in 84 eyes, the UCVA was 20/15 in 16 eyes (19.0%), 20/20 in 53 (63.1%), and 20/25 in 15 (17.9%). There was no loss of best spectacle-corrected visual acuity (BSCVA), and no eye required retreatment. CONCLUSION Laser-assisted subepithelial keratectomy for myopia provided excellent refractive and visual results with no loss of BSCVA and no serious complications. Subjective results and other measures of visual function need further evaluation.
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Fiore T, Carones F, Brancato R. Broad Beam vs. Flying Spot Excimer Laser: Refractive and Videokeratographic Outcomes of Two Different Ablation Profiles After Photorefractive Keratectomy. J Refract Surg 2001; 17:534-41. [PMID: 11583223 DOI: 10.3928/1081-597x-20010901-06] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the refractive outcomes and videokeratographic patterns in photorefractive keratectomy (PRK) of two last-generation excimer lasers: broad beam and flying spot lasers. METHODS Forty eyes were treated for a mean myopic correction of -5.59+/-2.17 D with a Ladarvision excimer laser (Autonomous Technology Corp). We compared the refractive outcomes and the videokeratographic patterns with those of 40 eyes treated with the Summit Apex Plus laser (Summit Technology Inc) for a mean myopic correction of -5.60+/-2.24 D. RESULTS During the 6-month follow-up, we found no significant difference in uncorrected and spectacle-corrected visual acuity, haze grade, regularity index, or decentration. The eyes treated by Ladarvision showed a lower refractive error at 1 month (P = .04), a lower incidence of central islands at 1 (P = .003) and 3 months (P = .04), a wider mean effective ablation area at 1 (P = .0004), 3 (P = .0000009), and 6 months (P = .0000000004), a less steep ablation edge at 1 (P = .0026), 3 (P = .015), and 6 months (P = .011). CONCLUSIONS The small beam excimer laser provides better videokeratographic outcomes, which lead to quicker refractive stability and better visual performance.
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Affiliation(s)
- T Fiore
- Department of Ophthalmology & Visual Sciences, San Raffaele Hospital, University of Milan, Italy
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Rachid MD, Yoo SH, Azar DT. Phototherapeutic keratectomy for decentration and central islands after photorefractive keratectomy. Ophthalmology 2001; 108:545-52. [PMID: 11237909 DOI: 10.1016/s0161-6420(00)00595-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
PURPOSE To determine visual outcomes after treatment of decentration and central islands occurring after photorefractive keratectomy (PRK). DESIGN Retrospective, noncomparative case series. PARTICIPANTS Patients (n = 14) who exhibited decentration or central islands after PRK and photoastigmatic keratectomy (PARK). METHODS Fourteen eyes with post-PRK decentration (group I) or central islands (group II) were treated by transepithelial phototherapeutic keratectomy guided by epithelial fluorescence without modulating agents, and subsequently were treated with PRK or PARK. Mean follow-up time was 9 months (range, 45 days-21 months). MAIN OUTCOME MEASURES We analyzed pre- and postoperative keratometry, refractive errors, uncorrected visual acuity (UCVA), best-corrected visual acuity, and haze. In group I, we also measured pre- and postoperative decentration; in group II, we compared pre- and postoperative central island power. RESULTS Group I showed improvement in centration (P = 0.003). Group II showed decreased central island power (P = 0.18). -LogMAR UCVA improved from 0.59 (20/80(+1)) to 0.17 (20/30) (P = 0.03) and from 0.74 (20/100(-1)) to 0.21 (20/30(-1)) (P = 0.01) after retreatment of groups I and II, respectively. CONCLUSIONS Retreatment of patients having decentration and central islands after PRK results in improved visual outcomes.
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Affiliation(s)
- M D Rachid
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02114, USA
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Fernández AP, Jaramillo J, Jaramillo M. Comparison of Photorefractive Keratectomy and Laser in situ Keratomileusis for Myopia of -6 D or Less Using the Nidek EC-5000 Laser. J Refract Surg 2000; 16:711-5. [PMID: 11110311 DOI: 10.3928/1081-597x-20001101-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE We compared the efficacy, predictability, and safety of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for the surgical correction of low and moderate myopia. METHODS A retrospective study was performed to evaluate uncorrected and spectacle-corrected visual acuity, and manifest refraction 1 year after PRK or LASIK. All procedures were done using an automatic microkeratome (Chiron Ophthalmic) and the Nidek EC-5000 excimer laser. RESULTS PRK was performed in 75 eyes of 45 patients and LASIK in 133 eyes of 77 patients. Mean age for PRK patients was 32.8 years (range, 18 to 52 yr) and LASIK patients was 29.6 years (range, 18 to 49 yr). Mean preoperative spherical equivalent refraction for PRK patients was -3.28 D (range, -1.00 to -6.00 D) and LASIK, -3.86 D (range, -1.00 to -6.00 D). One year after surgery, mean spherical equivalent refraction for Group 1 (baseline, -1.00 to -3.00 D) PRK eyes was -0.18 +/- 0.61 D (range, -1.50 to +0.75 D) and for LASIK eyes, -0.08 +/- 0.61 D (range, -1.50 to +1.62 D), with no statistically significant difference. For Group 2 eyes (baseline, -3.25 to -6.00 D), mean spherical equivalent refraction for PRK eyes was -0.44 +/- 0.87 D (range, -2.00 to +2.12 D) and for LASIK eyes, -0.09 +/- 0.83 D (range, -1.50 to +1.75 D), with no statistically significant difference. The antilogarithm of the mean UCVA (antilogUCVA) in Group 1 for PRK was 0.79 +/- 0.21 (20/25) and for LASIK was 0.87 +/- 0.19 (20/23), with no statistically significant difference. The antilogUCVA in Group 2 for PRK eyes was 0.70 +/- 0.24 (20/28) and for LASIK eyes was 0.83 +/- 0.18 (20/24), with a statistically significant difference (0.7 vs. 0.83, P < .005). The percentage of eyes with a postoperative UCVA >20/40 in Group 1 for PRK was 91.5% (38 eyes) and for LASIK was 95% (50 eyes) (no statistically significant difference), and in Group 2 for PRK eyes, it was 82% (27 eyes) and 97.5% (78 eyes) for LASIK (statistically significant difference, P < .05). CONCLUSION PRK and LASIK with the Nidek EC-5000 excimer laser are effective and safe for correcting low to moderate myopia, but LASIK eyes showed better results for moderate myopia in terms of uncorrected visual acuity.
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Keskinbora HK. Long-term results of multizone photorefractive keratectomy for myopia of -6.0 to -10.0 diopters. J Cataract Refract Surg 2000; 26:1484-91. [PMID: 11033395 DOI: 10.1016/s0886-3350(00)00563-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the 4 year refractive outcome of multizone photorefractive keratectomy (PRK) in eyes with high myopia. SETTING ++SSK Okmeydani Education Hospital, Eye Clinic, Türkiye Hospital, Okmeydani, Istanbul. METHODS Three ablation zones were used in 92 eyes of 48 patients whose refractive errors were between -6.0 and -10.0 diopters (D) (mean spherical equivalent -7.42 D +/- 1.25 [SD]). The zones were between 4.5 and 6.0 mm based on the thickness of the cornea and the refractive correction. After the epithelium healed, dexamethasone was applied 4 times a day during the first postoperative week and then fluorometholone was applied 4 times a day for a minimum of 4 weeks. If hyperopia was found post-PRK, the steroid dose was gradually tapered. The patients were examined 1 and 3 days postoperatively, 1, 2, and 4 weeks, every 3 months for the first year, and then every 6 months. RESULTS All patients were overcorrected in the first postoperative week. At 2 and 3 weeks, the mean manifest refraction was closer to emmetropia. At 6 months, the refraction was stable. The mean spherical equivalent was -0.10 D at the end of the first year, and stabilization continued for 4 years. After the third month, the haze regressed gradually without requiring treatment. In 1 patient, herpes simplex keratitis developed and healed in a short time with topical antiviral therapy. Nineteen eyes regressed more than -1.0 D, 4 eyes were overcorrected, 4 eyes had central islands (at 6 months), and 2 eyes were undercorrected. Two eyes were retreated for regression; 1 eye was retreated for undercorrection and 1 eye, for central island. An uncorrected visual acuity of 20/40 or better was achieved in 79.2% of eyes, and 73.9% were within +/-1. 0 D of the intended correction. CONCLUSION ++Photorefractive keratectomy was effective in treating high myopia between -6.0 and -10.0 D. The induced refractive changes stabilized between 6 and 9 months. In most patients, no significant regression was found after this period.
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Affiliation(s)
- H K Keskinbora
- SSK Okmeydani Education Hospital, Eye Clinic, Istanbul Türkiye Hospital, Okmeydani, Istanbul, Turkey.
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Abstract
PURPOSE To review the major advances in the field of refractive surgery occurring over the past 25 years. METHODS Literature review. RESULTS The major developments in refractive surgery over the past 25 years are reviewed. CONCLUSIONS The past 25 years have witnessed great changes in refractive surgery. As a result of advancements in technology, instrumentation, and technique, we have seen improvements in the treatment of all types of ametropias. In this article, we review some of the successes and failures of the past quarter-century.
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Affiliation(s)
- R D Stulting
- Cornea Service, Emory University School of Medicine, Department of Ophthalmology, Atlanta, Georgia, USA
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Vetrugno M, Maino A, Quaranta GM, Cardia L. A randomized, comparative open-label study on the efficacy of latanoprost and timolol in steroid induced ocular hypertension after photorefractive keratectomy. Eur J Ophthalmol 2000; 10:205-11. [PMID: 11071027 DOI: 10.1177/112067210001000303] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To evaluate the effect of 0.005% latanoprost and 0.50% timolol for the treatment of steroid-induced ocular hypertension (SIOH) after excimer laser photorefractive keratectomy (PRK). METHODS In this comparative, open-label study we enrolled 29 patients who received steroid therapy after PRK and developed intraocular pressure (IOP) elevation within 30 days of treatment. Fifteen were randomized to 0.005% latanoprost (group A) and 14 to 0.50% timolol (group B). IOP measurements were scheduled at 1, 3, 7, 15, 30, 60, 90 and 120 days of therapy. RESULTS; We did not find any real differences between latanoprost and timolol except at the 7-day and 15-day timepoints, when latanoprost reduced IOP significantly more than timolol (p=0.033, 0.035, respectively). After 7 days of therapy two of the 14 timolol-treated patients had high IOP (24 and 26 mmHg) but these promptly returned to normal when latanoprost was added. No significant differences were observed in the ocular side effects considered. CONCLUSIONS 0.005% latanoprost is as safe and effective as 0.50% timolol in the treatment of SIOH after PRK. Both drugs provide a significant and stable IOP reduction in the majority of patients after short-term treatment. These findings are encouraging for the use of latanoprost in the management of SIOH after PRK, although further trials are necessary to consider it as a primary treatment.
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Affiliation(s)
- M Vetrugno
- Department of Ophthalmology, Otorhinolaryngology, University of Bari, Italy.
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Lim L, Siow KL, Sakamoto R, Chong JS, Tan DT. Reverse geometry contact lens wear after photorefractive keratectomy, radial keratotomy, or penetrating keratoplasty. Cornea 2000; 19:320-4. [PMID: 10832691 DOI: 10.1097/00003226-200005000-00012] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine if a super diffusion coefficient of lens/lens thickness (Dk/L) reverse geometry gas permeable (steep peripheral and flatter central curve) contact lenses can be successfully worn after excimer photorefractive keratectomy (PRK), radial keratotomy (RK), or penetrating keratoplasty (PK). METHODS Patients with residual ametropia after PRK, RK, or PK were fitted with reverse geometry lenses (Plateau lens in SF-P material; Menicon USA, Inc, Clovis, CA, U.S.A.). Contact lens fit characteristics and comfort were assessed. Lens centration, visual quality, and ocular surface status were graded and visual acuity charted. RESULTS Thirteen eyes of 11 patients were fitted; eight eyes with PRK, one eye with RK, and four eyes with PK previously performed. The mean follow up of the patients was six months. The visual acuity prior to lenses ranged from 6/12 to counting fingers, and the acuity with lenses ranged from 6/6 to 6/30. Eight of the 11 patients wore the lenses the whole day without problems; 3 patients discontinued lens wear due to discomfort or unsatisfactory vision. CONCLUSIONS The combination of super Dk/L and reverse geometry lenses facilitate lens wear and is associated with good visual acuity.
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Affiliation(s)
- L Lim
- Singapore National Eye Centre, Singapore.
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O'Brart DP, Stephenson CG, Baldwin H, Ilari L, Marshall J. Hyperopic photorefractive keratectomy with the erodible mask and axicon system: two year follow-up. J Cataract Refract Surg 2000; 26:524-35. [PMID: 10771225 DOI: 10.1016/s0886-3350(00)00329-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To evaluate efficacy and long-term stability of hyperopic photorefractive keratectomy (H-PRK) using the erodible mask and Axicon system. SETTING Department of Ophthalmology, St. Thomas' Hospital, London, England. METHODS Forty-three patients (43 eyes), with a mean preoperative refraction (spherical equivalent) of +4.54 diopters (D) (range +1.75 to +7.50 D), were treated using an Apex Plus(R) excimer laser (Summit Technology). This uses an erodible mask to ablate a 6. 50 mm diameter hyperopic correction and an Axicon to fashion a 1.50 mm blend zone around the correction. The overall ablation diameter was 9.50 mm. Follow-up was 2 years. RESULTS At 2 years, the mean manifest refraction was +0.16 D (range +4.125 to -4.000 D), with the induced correction appearing stable after 9 months. Based on the Munnerlyn algorithm, predictability was acceptable for corrections up to +4.50 D, with 68% of eyes within +/-1.00 D of the predicted correction. It was poorer for +6.00 D corrections, with 33% of eyes within +/-1.00 D of that expected. Patient satisfaction was high. Forty eyes (93%) had an improvement in uncorrected near visual acuity and 37 (86%), an improvement in uncorrected distance acuity. A peripheral ring of haze, 6.5 mm in diameter, appeared in all eyes 1 month postoperatively. Its intensity was maximal at 3 to 9 months and then diminished over time. There were no significant differences in measurements of the central corneal transparency at 12 and 24 months and those preoperatively. Measurements of flicker contrast sensitivity, forward light scatter (glare), and scotopic halos showed no significant differences between preoperative values and those measured after 6 months. CONCLUSIONS Achieved H-PRK corrections with the erodible mask and Axicon system agreed closely with the Munnerlyn algorithm, with refractive stability after 9 months. Predictability was acceptable for corrections up to +4.50 D. Axial corneal transparency was not compromised and visual performance, in terms of best spectacle-corrected visual acuity, forward light scatter, and night halos, was not impaired.
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Affiliation(s)
- D P O'Brart
- Department of Ophthalmology, United Medical and Dental Schools, St. Thomas' Hospital, London, England, UK
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Sener B, Ozdamar A, Aras C. Apical nodular subepithelial corneal scar after retreatment in hyperopic photorefractive keratectomy. J Cataract Refract Surg 2000; 26:352-7. [PMID: 10713228 DOI: 10.1016/s0886-3350(99)00411-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To report a complication, apical nodular subepithelial corneal scar, that can occur after hyperopic photorefractive keratectomy (PRK) retreatment. SETTING Istanbul University Eye Research Center, Istanbul, Turkey. METHODS Twelve eyes of 6 patients with apical nodular subepithelial corneal scar were retrospectively studied. Mean age of the 5 men and 1 woman was 30.2 years +/- 5.4 (SD). All eyes had hyperopic PRK retreatment for regression 9.5 +/- 1.44 months after primary hyperopic PRK. Mean spherical equivalent refraction of the residual hyperopia before retreatment was +4.67 +/- 0.81 diopters (D). All patients had a corneal haze grade of less than 1+. Hyperopic PRK retreatment was performed with a 193 nm excimer laser (Chiron Technolas Keracor 116). RESULTS Apical nodular subepithelial corneal scars developed within the first month of hyperopic PRK retreatment and progressed until the third month in 12 eyes of 6 patients. The lesion was round and symmetrical in both eyes, smaller than 2.0 mm, and centrally located. During the mean 40.66 +/- 2.46 month follow-up, the lesion did not change in size or density. Mean spherical equivalent refraction after retreatment was 2.88 +/- 0.88 D (range +1.50 to +4.00 D) at 1 month and +4.36 +/- 1.83 D at last follow-up. Refraction was unmeasurable in 3 eyes. Five eyes lost 1 line of best spectacle-corrected visual acuity and 7 eyes, 2 or more lines. The surface regularity indexes were higher than 2.00 in all the eyes. CONCLUSION Hyperopic PRK retreatment may cause the sight-threatening complication of apical nodular subepithelial corneal scar. This complication behaves unlike corneal haze and does not resolve spontaneously over time.
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Affiliation(s)
- B Sener
- Istanbul University Eye Research Center, Istanbul, Turkey
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Fisher EM, Ginsberg NE, Scher KS, Hersh PS. Photorefractive keratectomy for myopia with a 15 Hz repetition rate. J Cataract Refract Surg 2000; 26:363-8. [PMID: 10713230 DOI: 10.1016/s0886-3350(99)00406-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To evaluate excimer laser photorefractive keratectomy (PRK) for myopia using a repetition rate of 15 Hz instead of 10 Hz. SETTING The Cornea and Laser Eye Institute, Teaneck, and Department of Ophthalmology, UMDNJ-New Jersey Medical School, Newark, New Jersey, USA. METHODS Photorefractive keratectomy using a 15 Hz repetition rate was performed in 23 eyes of 14 patients by a single surgeon at 1 center. The attempted corrections ranged from -2.8 diopters (D) to -5.5 D. Preoperative and postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), predictability, corneal haze, and subjective glare/halo were evaluated over 6 months. RESULTS At 6 months, UCVA was 20/32 or better in all eyes and at least 20/20 in 14 eyes (73.7%). Two eyes (10.5%) lost 2 or more Snellen lines of BSCVA; postoperative BSCVA was at least 20/25 in 100% of eyes and 20/20 or better in 95.0%. Fifteen eyes (78.9%) were within +/-0.5 D of attempted correction, and 19 (100%) were within +/-1.0 D. Mean spherical equivalent refraction was -4.62 D preoperatively, +0.15 D at 1 month, -0.09 D at 3 months, and -0.37 D at 6 months. At 6 months, 4 eyes (21.0%) had no corneal haze and 14 (73.7%) had trace subepithelial haze. Fifteen eyes (78.9%) had no glare/halo effect at 6 months, and 4 (21.0%) had minimal glare/halo effect. CONCLUSIONS Clinical outcomes after excimer laser PRK for myopia using an increased repetition rate of 15 Hz were good and similar to those in studies conducted with a 10 Hz repetition rate.
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Affiliation(s)
- E M Fisher
- Department of Ophthalmology, UMDNJ-New Jersey Medical School, Newark, New Jersey 07103-2499, USA
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Kapadia MS, Krishna R, Shah S, Wilson SE. Surgically induced astigmatism after photorefractive keratectomy with the excimer laser. Cornea 2000; 19:174-9. [PMID: 10746449 DOI: 10.1097/00003226-200003000-00010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate retrospectively the effect of spherical excimer laser photorefractive keratectomy (PRK) on astigmatism. METHODS Four hundred seventy consecutive eyes of patients who had PRK for the treatment of myopia without astigmatic keratotomy, PRK reoperation, or other surgical procedures were evaluated in a retrospective clinical study. PRK was performed using the Summit Apex excimer laser with attempted corrections from 1 to 7 diopters (D) of myopia. Preoperative and postoperative astigmatism was determined by manifest refraction refined with a 0.25-D Jackson cross cylinder and evaluated with vector analysis. RESULTS Eighty-five ( 18%) eyes continued to have a spherical refraction after PRK, 53 (11%) eyes had the same preoperative astigmatism, and 332 (71%) eyes had a change in magnitude of astigmatism > or =0.25 D after spherical PRK. The absolute change in astigmatism magnitude irrespective of axis was +0.4 +/- 0.4 (standard deviation) D at 6 months after PRK. Eyes with change in astigmatism power tended to have higher preoperative myopia and higher preoperative astigmatism. Vector analysis revealed surgically induced astigmatism was 0.68 +/- 0.50 D (range, 0-3.25 D) at 1 month and 0.56 +/- 0.47 D (range, 0-3.1 D) at 12 months after spherical PRK. CONCLUSION Spherical excimer laser PRK is associated with significant surgically induced astigmatism that is likely related to decentration of the ablation, excimer laser beam irregularities, and variations in wound healing across the ablated zone. Surgically induced astigmatism will complicate attempts to correct astigmatism simultaneously at the time of PRK and suggest that such attempts are likely to be problematic for lower levels of astigmatism.
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Affiliation(s)
- M S Kapadia
- Eye Institute, The Cleveland Clinic Foundation, Ohio, USA
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Patterson A, Kaye SB, O'Donnell NP. Comprehensive method of analyzing the results of photoastigmatic refractive keratectomy for the treatment of post-cataract myopic anisometropia. J Cataract Refract Surg 2000; 26:229-36. [PMID: 10683790 DOI: 10.1016/s0886-3350(99)00362-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE To assess the efficacy, stability, and safety of photoastigmatic refractive keratectomy (PARK) in treating post-cataract myopic anisometropia to restore binocularity and to describe a comprehensive method for analyzing the results of refractive surgery. SETTING St. Paul's Eye Center, Royal Liverpool Hospital, Liverpool, United Kingdom. METHODS Nineteen patients (20 eyes) with post-cataract myopic anisometropia were treated with PARK using a VISX Twenty-Twenty laser and followed for 12 months. Cataract surgery had been performed between 10 and 144 months (mean 43.4 months) previously. A comprehensive method based on Long's matrix formalism and the vech operator of Harris, in addition to the nearest equivalent sphere and cylinder, was used to analyze the refractive data. RESULTS The mean preoperative refraction in the post-cataract eyes was -4.79 +1.17 x 0.2 and in the fellow eyes, +0.02 +0.31 x 166. Twelve months after PARK, the postoperative refraction in the post-cataract eyes was -0.90 +0.65 x 2, a significant reduction (P = .15). This postoperative refraction was not significantly different from that in the fellow eye (P = .93). The pretreatment mean uncorrected visual acuity was 0.12. It improved to 0.41 at 12 months, at which time 52% of eyes achieved a visual acuity of 0.5 or better without correction. All patients regained binocularity. At 12 months, 2 eyes (11%) showed clinically unacceptable regression; 1 eye with grade 2 haze lost 1 line of corrected visual acuity. CONCLUSIONS Photoastigmatic refractive keratectomy reduced post-cataract myopic anisometropia, allowing restoration of binocularity in all patients. Overall, the results in this elderly population with previous ocular surgery, posterior capsule thickening, and macular degeneration are not as satisfactory as those obtained from similar treatment of physiological myopia. Stability and postoperative complications are acceptable.
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Affiliation(s)
- A Patterson
- St. Paul's Eye Unit, Royal Liverpool University Hospital, United Kingdom
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Kapadia MS, Krishna R, Shah S, Wilson SE. Arcuate Transverse Keratotomy Remains a Useful Adjunct to Correct Astigmatism in Conjunction With Photorefractive Keratectomy. J Refract Surg 2000; 16:60-8. [PMID: 10693620 DOI: 10.3928/1081-597x-20000101-08] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To retrospectively evaluate the effectiveness of paired, arcuate transverse keratotomy (Arc-T) performed prior to or after photorefractive keratectomy (PRK) to correct low to moderate amounts of natural or laser-induced astigmatism. METHODS Spherical PRK was performed in 730 eyes for myopia of -1.00 to -7.00 D. PRK with arcuate transverse keratotomy was performed in 150 of these eyes; we studied 123 eyes that did not have PRK enhancement. Arc-T was performed prior to PRK in all 37 study eyes with astigmatism of 1.50 D or more at the preoperative examination. Arc-T keratotomy was performed after PRK in 86 study eyes for residual astigmatism of +0.75 D or more and uncorrected visual acuity of 20/30 or worse. RESULTS Arc-T before PRK group: PRK was performed at a mean 1.0 +/- 1.5 months after Arc-T. Mean astigmatism decreased from +2.40 +/- 0.6 D (range, 1.00 to 4.00 D) before Arc-T to 0.60 +/- 0.60 D (range, 0 to 2.25 D) after Arc-T (P < .0001). Net change in astigmatism was 1.80 +/- 0.60 D (range, 0.80 to 2.80 D) and mean reduction was 75%. Spherical equivalent refraction changed from -4.10 +/- 1.90 D (range, -0.25 to -8.10 D) to -4.40 +/- 1.80 D after Arc-T (P = .002). Mean change in spherical equivalent refraction after Arc-T was -0.30 +/- 0.50 D (range, -1.10 to +0.40 D). Arc-T after PRK group: Arc-T was performed at a mean 3.5 +/- 1.9 months after PRK. Six months after Arc-T, astigmatism was decreased from +1.50 +/- 0.60 D to 0.40 +/- 0.40 D (P = .04). Net change in astigmatism at 6 months was 1.10 +/- 0.60 D and mean reduction was 74%. Vector change in astigmatism magnitude was 1.30 +/- 0.60 D (range, 0 to 4.00 D) at 6 months and vector change in astigmatism axis was 65 degrees +/- 68 degrees. Spherical equivalent refraction did not change when Arc-T was performed after PRK for eyes with low astigmatism (P = .4). Arc-T retreatment was performed in 6 of 37 (16%) eyes that had Arc-T before PRK and 18 of 86 (21%) eyes that had Arc-T after PRK (P = .12). CONCLUSION Arcuate transverse keratotomy performed prior to PRK for high astigmatism or after PRK for lower levels of residual astigmatism effectively improved visual outcome. Coupling was less predictable for high levels of astigmatism correction with Arc-T.
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Affiliation(s)
- M S Kapadia
- Eye Institute and Department of Cell Biology, The Cleveland Clinic Foundation, OH, USA
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Vetrugno M, Quaranta GM, Maino A, Cardia L. A randomized, comparative study of fluorometholone 0.2% and fluorometholone 0.1% acetate after photorefractive keratectomy. Eur J Ophthalmol 2000; 10:39-45. [PMID: 10744204 DOI: 10.1177/112067210001000107] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To compare the efficacy and tolerance of fluorometholone 0.1% acetate and fluorometholone 0.2% eyedrops in the postoperative management of photorefractive keratectomy (PRK). METHODS A randomised single-blind comparative study was performed on two groups of 30 patients who underwent myopic PRK. The first group was given fluorometholone 0.1% acetate and the second fluorometholone 0.2%. Uncorrected and best corrected visual acuity, haze, IOP and local tolerance were evaluated. Statistical analysis was done using parametric and non-parametric tests. RESULTS Visual acuity did not differ in the two groups; both were homogeneous as far as refractive error and haze were concerned. Three patients (10%) treated with fluorometholone 0.2% and two patients (6.6%) with fluorometholone 0.1% acetate developed ocular hypertension, but this was not statistically significant. CONCLUSIONS Fluorometholone 0.1% acetate was effective on inflammation after PRK, with the same efficacy as fluorometholone 0.2%.
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Affiliation(s)
- M Vetrugno
- Department of Ophthalmology and Otorhinolaryngology, University of Bari, Italy.
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Artola A, Ayala MJ, Claramonte P, Pérez-Santonja JJ, Alió JL. Photorefractive keratectomy for residual myopia after cataract surgery. J Cataract Refract Surg 1999; 25:1456-60. [PMID: 10569159 DOI: 10.1016/s0886-3350(99)00233-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the effectiveness, predictability, and safety of photorefractive keratectomy (PRK) for correcting residual myopia and myopic astigmatism after cataract surgery with intraocular lens implantation. SETTING Refractive Surgery and Cornea Unit, Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS Thirty consecutive eyes (30 patients) had PRK for residual myopia after cataract surgery. Surface PRK with a VISX Twenty-Twenty excimer laser was used in all patients. Follow-up was 1 year. RESULTS Before PRK, no eye had an uncorrected visual acuity (UCVA) of 20/40 or better. Twelve months after PRK, 16 eyes (53.33%) had a UCVA of 20/40 or better. After PRK, best corrected visual acuity (BCVA) improved 1 line or more in 14 eyes (46.66%) over the preoperative values, and 15 eyes (50.00%) had the same BCVA as before PRK. Mean pre-PRK refraction of -5.00 diopters (D) +/- 2.50 (SD) decreased significantly to -0.25 +/- 0.50 D at 12 months (P < .001). At 12 months, the spherical equivalent was within +/- 1.00 D of emmetropia in 27 eyes (90.00%). No vision-threatening complications occurred. CONCLUSION Photorefractive keratectomy was an effective, predictable, and safe procedure for correcting residual myopia and myopic astigmatism after cataract surgery.
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Affiliation(s)
- A Artola
- Refractive Surgery and Cornea Department, Alicante Institute of Ophthalmology, Miguel Hernández University School of Medicine, Spain
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Ahn CS, Clinch TE, Moshirfar M, Weis JR, Hutchinson CB. Initial results of photorefractive keratectomy and laser in situ keratomileusis performed by a single surgeon. J Cataract Refract Surg 1999; 25:1048-55. [PMID: 10445189 DOI: 10.1016/s0886-3350(99)00127-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To determine the safety and efficacy of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) early in a surgeon's experience. SETTING Ophthalmology Department, John A. Moran Eye Center, Salt Lake City, Utah, USA. METHODS Between October 1995 and April 1997, a retrospective analysis was performed of 200 eyes in 128 patients who had PRK or LASIK with a follow-up of at least 3 months. The mean age was 38.1 years +/- 10.4 (SD) in the PRK group and 42.3 +/- 10.1 years in the LASIK group. There were 36 women and 30 men in the former and 32 women and 30 men in the latter. Photorefractive keratectomy, PRK/astigmatic keratotomy (AK), LASIK, or LASIK/AK was performed with the Summit Omnimed excimer laser. Preoperative evaluation included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, tonometry, and computerized videokeratography. At 1, 3, and 6 months, UCVA, BSCVA, mean spherical equivalent (SE), astigmatism, corneal haze, subjective vision (day, night, glare, and halo), and complications were measured. RESULTS Mean SE was 0.16 +/- 0.82 diopter (D) in the PRK group and -0.09 +/- 0.63 D in the LASIK group at 1 month (P < .05), -0.18 +/- 0.66 D and -0.16 +/- 0.58 D, respectively, at 3 months, and -0.33 +/- 0.73 D and -0.09 +/- 0.62 D, respectively, at 6 months. Achieved correction was similar in the 2 groups. Mean BSCVA was 22.8 +/- 6.0 in the PRK group and 22.2 +/- 5.3 in the LASIK group at 1 month, 21.1 +/- 6.0 and 21.1 +/- 3.1, respectively, at 3 months, and 19.8 +/- 3.5 and 22.9 +/- 5.2, respectively, at 6 months (P < .005). Mean surface regularity index was 0.68 +/- 0.40 in the PRK group and 0.86 +/- 0.41 in the LASIK group at 1 month, 0.54 +/- 0.26 and 0.72 +/- 0.37, respectively, at 3 months (P < .05), and 0.49 +/- 0.27 and 0.84 +/- 0.42, respectively, at 6 months. Mean surface asymmetry index was 0.71 +/- 0.43 in the PRK group and 0.55 +/- 0.21 in the LASIK group at 1 month (P < .05), 0.53 +/- 0.24 and 0.51 +/- 0.23, respectively, at 3 months, and 0.46 +/- 0.19 and 0.64 +/- 0.54, respectively, at 6 months. The subjective parameters between the groups were significantly different only at 6 months; patients in the PRK group reported better day and night vision. CONCLUSION With careful preparation and proper training, PRK and LASIK appear to be safe and efficacious even during the surgeon's early learning phases.
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Affiliation(s)
- C S Ahn
- University of Utah Health Science Center, Salt Lake City, USA
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Abstract
The development of excimer laser technology, coupled with advances in lamellar corneal surgery, has heralded a new era in the treatment of refractive errors. This paper discusses the current status of hyperopic laser-assisted in situ keratomileusis. This surgical modality is at a relatively early stage of investigation but appears to offer promise for the surgical correction of hyperopia. This paper considers the evolution of the technique, analyzes the current literature, and discusses the current indications, limitations, and possible future developments.
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Affiliation(s)
- D P O'Brart
- Department of Ophthalmology, St. Thomas' Hospital, London, UK
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Coorpender SJ, Klyce SD, McDonald MB, Doubrava MW, Kim CK, Tan AL, Srivannaboon S. Corneal topography of small-beam tracking excimer laser photorefractive keratectomy. J Cataract Refract Surg 1999; 25:674-84. [PMID: 10330644 DOI: 10.1016/s0886-3350(99)00015-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To evaluate the topographic characteristic of photorefractive keratectomy (PRK) for low myopia performed with a small-beam (0.9 mm) tracking excimer laser. SETTING Department of Ophthalmology, LSU Eye Center, Louisiana State University Medical Center School of Medicine in New Orleans, and the Refractive Surgery Center of the South at the Eye, Ear, Nose, & Throat Hospital, New Orleans, Louisiana, USA. METHODS Sixty-seven eyes of 47 patients had PRK with a small-beam tracking laser. Of these, 49 eyes had data permitting evaluation of ablation centration; usable data for topographic analysis were available for 59 eyes preoperatively, 54 eyes at 1 month, 42 eyes at 3 months, and 25 eyes at 6 months, permitting measurement of various topographic parameters, including the cylinder (CYL), average corneal power (ACP), surface regularity index (SRI), surface asymmetry index (SAI), corneal eccentricity index (CEI), and coefficient of variation of corneal power (CVP). RESULTS Preoperatively, all eyes were topographically normal. Postoperatively, no eye exhibited a "central island" by even the least-restrictive definition, and all eyes had best spectacle-corrected visual acuities (BSCVAs) of 20/20 or better at all follow-ups. Mean decentration of the ablations from the pupil centers was 0.42 mm +/- 0.28 (SD) (n = 49). There was no correlation between measured decentration and BSCVA (P = .46). The central cornea was flattened (decreased ACP; P < .001) and made oblate (decreased CEI; P < .001) as expected. There was no increase in SRI or SAI (irregular astigmatism) at 6 months compared with preoperative values (P = .91); however, CYL and CVP (varifocality) increased slightly (P = .04 and .02, respectively). CONCLUSION The absence of significant regular or irregular astigmatism 6 months after PRK with the small-beam laser is an improvement over published results achieved with wide-beam lasers and is consistent with the excellent visual acuity results in this cohort.
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