Photorefractive Keratectomy For Hyperopia and Aphakia with a Scanning Spot Excimer Laser

Surgical Correction of Hyperopia

Surgical attempts to correct hyperopia have yielded varying results over the last 130 years. These techniques include the reshaping of the cornea through incisions, burns, or lamellar cuts with removal of peripheral tissue; the addition of central inlays; laser ablations; and the replacement of the crystalline lens. By examining the success of each surgical technique, the refractive surgeon may be able to make an informed decision on its indications and limitations, based on the specific patient's characteristics. Reporting the outcomes and complications of hyperopic surgery will help refine our approach to the management of an increasingly hyperopic and presbyopic population.

First Clinical Experience With the Alcon LADAR 6000 Excimer Laser

PURPOSE

To evaluate the reliability and ergonomics and to assess the first clinical results provided by the new LADAR 6000 excimer laser used to correct myopia and astigmatism, both by conventional and wavefront-guided ablation.

METHODS

Seventy-four consecutive eyes from 37 patients underwent LASIK as the first field evaluation protocol of the Alcon LADAR 6000 excimer laser. Forty-six eyes were treated by wavefront-guided ablation to correct a manifest spheroequivalent refractive error (MSRE) of -0.50 to -9.75 diopters (D) (mean: -4.19 D, cylinder range: 0.0 to -3.50 D). Twenty-eight eyes were treated by conventional ablation to correct MSRE of -1.00 to -7.00 D (mean: -3.11 D, cylinder range: 0.0 to -1.75 D). Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), MSRE, and wavefront measurements were assessed. Follow-up was 3 months for all eyes.

RESULTS

Three months after surgery, all eyes were within +/- 1.00 D of intended correction. Forty-three (93.5%) eyes treated with wavefront-guided ablation and 25 (89.3%) eyes treated with conventional ablation were within +/- 0.50 D. All eyes reached > or = 20/25 UCVA. UCVA > or = 20/20 was reached in 45 (97.8%) wavefront-guided eyes and 26 (92.9%) conventional eyes; 37 (80.4%) wavefront-guided eyes and 17 (60.7%) conventional eyes had 20/16 UCVA. None of the eyes treated lost > or = 2 lines of BSCVA.

CONCLUSIONS

The LADAR 6000 excimer laser results proved to be at least as accurate, predictable, and safe as the results currently achieved with the LADARVision4000 excimer laser. The improved microscope illumination enhances visibility for better consistency and ease of use. The better ergonomics and software design of this platform improved patient flow.

Photorefractive keratectomy versus laser in situ keratomileusis for the treatment of spherical hyperopia

OBJECTIVE

To compare photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in treating spherical hyperopia using the VISX STAR S2 excimer laser.

INTERVENTION

Fifteen consecutive eyes of 15 patients underwent PRK, and 16 consecutive eyes of 16 patients underwent LASIK (follow-up: 12 months).

MAIN OUTCOME MEASURES

Postoperative pain, uncorrected visual acuity (UCVA), deviation from intended correction, and loss of best spectacle-corrected visual acuity (BSCVA).

RESULTS

Mean preoperative spherical equivalent was + 2.18 diopter [D] for PRK and + 2.03D for LASIK. All PRK patients experienced significant postoperative pain that required systemic medication, whereas LASIK patients had minor and transient discomfort. Mean deviation from intended correction was -0.83D, + 0.01D, and + 0.18D at 1, 6, and 12 months after PRK, and + 0.22D, +0.30D, and + 0.40D at 1, 6, and 12 months after LASIK (P = 0.002 at 1 month). A higher proportion of LASIK eyes had a UCVA of 20/20 or better at all time points (P = 0.013 and 0.025 at 1 and 3 months, respectively). There was no statistically significant difference between both groups in BSCVA loss.

CONCLUSIONS

LASIK and PRK are comparable in efficacy and safety. However, PRK was more painful, with an initial and temporary myopic over-correction that did not occur after LASIK. Stability was achieved between 3 and 6 months following PRK, and one month following LASIK.

Phakic refractive lens experience in Spain

PURPOSE

To evaluate the efficacy, predictability, and safety of a phakic refractive lens (PRL) for high myopia and hyperopia.

SETTING

Instituto Oftalmológico Hoyos, Barcelona, Spain.

METHODS

A PRL was implanted in 31 eyes (17 myopic, 14 hyperopic) with a mean preoperative spherical equivalent (SE) of -18.46 diopters (D) (range -11.85 to -26.00 D) for myopia and +7.77 D (range +5.25 to +11.00 D) for hyperopia. All eyes had a thorough ophthalmologic examination before and after surgery. The follow-up was at least 12 months.

RESULTS

At 1 year, the mean postoperative SE in the myopic group was -0.22 D +/- 0.87 (SD) and 82% were within +/-1.00 D of the desired refraction. The mean postoperative SE in the hyperopic group was -0.38 +/- 0.82 D, and 79% were within +/-1.00 D. Snellen lines of visual acuity were gained in 65% of the myopic eyes (8 eyes gained 1 line, 3 eyes gained 2 lines), and no eye lost lines. In the hyperopic group, 1 eye gained 1 line of acuity and 1 eye lost 1 line. In the hyperopic group, complications included pupillary block in 2 eyes and pigment dispersion signs without intraocular hypertension in 1 eye. In the myopic group, 1 eye had a corticosteroid-induced intraocular pressure rise, 1 eye had a spot of anterior cortical lens opacity immediately after surgery that did not progress, and 3 eyes with the PRL model 100 had decentration that required replacement of the lens. Four patients (2 myopic, 2 hyperopic) reported night halos in both eyes.

CONCLUSIONS

Results indicate that PRL implantation to correct high myopia and hyperopia is a relatively rapid, safe, predictable, and stable method that in many cases also improves the best corrected visual acuity. Complications such as visually significant progressive cataract and pigmentary glaucoma were not observed.

Hyperopic laser in situ keratomileusis for refractive accommodative esotropia

PURPOSE

To assess the efficacy of hyperopic laser in situ keratomileusis (LASIK) in creating orthophoria without optical correction in adult patients with refractive accommodative esotropia (RAE).

SETTING

Instituto Oftalmológico de Sabadell, Sabadell, Barcelona, Spain.

METHODS

This prospective single-center clinical trial studied 9 eyes (18 patients) with RAE having hyperopic LASIK. The mean follow-up was 20 months (range 12 to 24 months). The mean preoperative refraction was +5.01 diopters (D) and the mean deviation angle without optical correction, 36 prism diopters. The intervention was hyperopic LASIK using the Automated Corneal Shaper microkeratome (Bausch & Lomb) and the Apollo broad-beam excimer laser using a 5.5 mm optical zone and an 8.0 mm transition zone; astigmatism was treated by steepening the flattest meridian.

RESULTS

All patients achieved orthophoria or the preoperative microtropia without optical correction immediately after surgery. This was maintained throughout the follow-up. Fifty-six percent of all cases were within +/-0.5 D of emmetropia, and 89% were within +/-1.0 D. The uncorrected visual acuity improved significantly (P <.005), especially at near, and the mean best corrected visual acuity (BCVA) was maintained, although 4 eyes (22%) lost 1 line of BCVA. There were no significant complications.

CONCLUSIONS

In adult patients with RAE, treatment of the refractive error using hyperopic LASIK was safe and effective and corrected the esodeviation. Further studies in younger patients will help determine the age at which this intervention may be indicated.

Laser in situ Keratomileusis for the Correction of Hyperopia From +0.50 to +11.50 Diopters With the Keracor 117C Laser

PURPOSE

To evaluate excimer laser in situ keratomileusis (LASIK) for the correction of hyperopia.

METHODS

We reviewed retrospectively the medical records of 46 patients treated with LASIK for hyperopia. All patients had a complete ophthalmologic evaluation. The corneal bed was ablated using the Bausch & Lomb Chiron Keracor 117C excimer laser to create a paracentral annular ablation under a nasally hinged 160-microm corneal flap with the Chiron Automatic Corneal Shaper microkeratome. Follow-up was a minimum of 6 months.

RESULTS

Eighty eyes of 46 patients (23 males and 23 females) were included. Age ranged from 18 to 65 years (mean, 42 yr). The range of preoperative spherical equivalent refraction was +0.50 to +11.50 D (mean, +3.40 D). Mean postoperative spherical equivalent refraction at 6 months was +0.26 D. Six months after surgery, 35 eyes (44%) achieved uncorrected visual acuity of 20/20 or better and 78 eyes (97.5%) achieved 20/40 or better. Forty-six eyes (58%) had a postoperative spherical equivalent refraction within +/-0.50 D of attempted correction, and 67 eyes (84%) were within +/-1.00 D of attempted correction. When using the Bausch & Lomb Chiron Keracor 117C excimer laser to correct hyperopia, eyes with a spherical equivalent refraction less +2.00 D should be overcorrected by 25%, +2.00 to +4.00 D by 30%, and over +4.00 by 40%. The positive cylinder should be overcorrected by 10%.

CONCLUSIONS

LASIK was safe and effective in the treatment of hyperopia from +0.50 to +11.50 D. Regression following LASIK for hyperopia remains a problem. A special nomogram was required to achieve results comparable with those for myopia.

Prospective Study of Photorefractive Keratectomy for Hyperopia Using an Axicon Lens and Erodible Mask

PURPOSE

To evaluate prospectively the long-term safety, efficacy, and visual performance following photorefractive keratectomy (PRK) for hyperopia using an erodible mask and axicon lens system.

METHODS

Eighteen eyes of 9 patients with a mean preoperative spherical equivalent refraction of +2.26 +/- 0.82 D (range, +1.13 to +4.00 D) underwent PRK with the Summit Apex Plus excimer laser following manual scraping of the epithelium. Eyes were prospectively evaluated 1, 3, 6, 9, 12, 18, and 24 months following the procedure. Primary outcome variables included cycloplegic refraction and uncorrected visual acuity (UCVA). Visual performance was determined by contrast sensitivity measurements under scotopic (21 lux) and photopic (324 lux) conditions and best spectacle-corrected visual acuity (BSCVA) under scotopic, photopic, and glare conditions.

RESULTS

For 18 eyes, 98.2% of the mean preoperative spherical equivalent refraction was corrected to +0.04 +/- 0.87 D (range, -1.38 to +2.00 D) at 24 months after PRK. Twelve eyes (67%) were within +/-0.50 D of attempted correction and 15 eyes (83%) were within +/-1.00 D. Stability within +/-0.50 D was achieved after 6 months. Two eyes (11%) experienced almost complete regression of the refractive effect. There was no statistically significant decrease in contrast sensitivity under scotopic or photopic conditions. (P > .05). Best spectacle-corrected visual acuity showed progressive improvement in the early postoperative period. By 24 months, 0 eyes (0%) lost 2 or more lines of BSCVA under scotopic and photopic conditions and 1 eye (5.5%) lost 2 or more lines under glare conditions. Fourteen eyes (78%) had grade 1 to 3 anterior stromal haze at 24 months which was characteristically mid-peripheral and did not adversely affect visual performance.

CONCLUSION

Photorefractive keratectomy with the the Summit Apex Plus excimer laser for low to moderate hyperopia resulted in an effective reduction of hyperopia without compromising long-term visual performance. Stability and recovery of distance uncorrected and best spectacle-corrected visual acuity took approximately 6 months.

Apical nodular subepithelial corneal scar after retreatment in hyperopic photorefractive keratectomy

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.

Central bump-like opacity as a complication of high hyperopic photorefractive keratectomy

PURPOSE

A new complication is reported in association with high hyperopic excimer laser photorefractive keratectomy.

METHODS

One thousand consecutive eyes were treated with a Meditec MEL-60 excimer laser (Meditec Inc, Heroldsberg, Germany) for hyperopic refractive error between +1 diopters and +7 diopters.

RESULTS

Three eyes with high hyperopic corrections between +5 and +6 diopters had a central, round bump-like subepithelial scar develop 1 month after hyperopic photorefractive keratectomy, which reduced the uncorrected and spectacle-corrected visual acuity.

CONCLUSION

Central bump-like opacity is a new, visually significant complication of unknown origin associated with high hyperopic photorefractive keratectomy. Possible causes of this complication include drying and edema of the cornea as a result of prolonged exposure, interruption of the peripheral superficial nerve plexus affecting the central anterior stroma, and abnormal epithelial or tear film function resulting from excessive central steeping.

Photorefractive keratectomy for hyperopia: long-term nonlinear and vector analysis of refractive outcome

PURPOSE

To characterize the refractive changes after excimer laser photorefractive keratectomy for the correction of hyperopia over a follow-up up to 3 years and to assess refractive stability and changes in astigmatism.

DESIGN

Noncomparative, nonrandomized, retrospective, interventional case series.

PARTICIPANTS

Thirty-eight hyperopic eyes of 28 patients (age range, 33-62 years) with refraction in the range +1.00 to +8.00 diopters (D). Mean attempted correction was +3.33+/-0.98 D (range, +1.00 to +4.00 D). Data were compared to those from 216 eyes treated for myopia in the range -1.00 to -12.70 D.

INTERVENTION

The hyperopic correction was made using an erodible mask inserted in 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 3 to 11 times (5.5+/-2.4) over a 3- to 34-month follow-up (16.8+/-8.4 months).

MAIN OUTCOME MEASURES

Vector analysis of refractive error, applying a nonlinear statistical model fitting the spherical equivalent, and the sphere component data. The fit parameters were the long-term error at stabilization (epsilon(infinity)), the amount of regression (epsilon0), being the difference of refractive errors immediately after surgery and at stabilization, and the time constant (T1/2) giving the temporal scale length by which the overcorrection halves (regression half-life). Cylinder was analyzed by a linear regression.

RESULTS

The initial overcorrection was much larger after hyperopic treatments than myopic ones (epsilon0 = -3.26+/-0.35 D vs. +1.43+/-0.35 D), and it takes typically four times longer to regress (T1/2 = 3.30+/-0.91 months). Refractive stabilization is reached after more than 1 year, with a satisfactory refractive result. The hyperopic treatment induces a mean astigmatism of 1.00 D, which remains constant throughout the follow-up, and tends to be aligned along the with-the-rule meridian.

CONCLUSIONS

The advantages of a reasonably well-designed algorithm to correct hyperopia (epsilon(infinity) = +0.20+/-0.23 D) are counterbalanced by the long time to refractive stabilization and by the induced astigmatism.

LASIK for hyperopia and hyperopic astigmatism--results of a pilot study

Laser-assisted in situ keratomileusis (LASIK) was evaluated in hyperopia and hyperopic astigmatism. LASIK was safe and effective in spherical hyperopia up to +5 D and acceptable in toric hyperopia up to +5 D but results were poor in hyperopia of more than +5 D.