Asymmetric intracorneal ring segments in the treatment of snowman phenotype keratoconus

OBJECTIVE

To evaluate refractive, aberrometric, topographic, and topometric outcomes of asymmetric intracorneal ring segment (ICRS) implantation in snowman phenotype (asymmetric bow-tie) keratoconus.

METHODS

This retrospective, interventional study included eyes with snowman phenotype keratoconus. Two asymmetric ICRSs (Keraring AS) were implanted after femtosecond laser-assisted tunnel formation. Visual, refractive, aberrometric, topographic, and topometric changes after asymmetric ICRS implantation were evaluated with a mean follow-up of 11 months (6-24 months).

MAIN RESULTS

Seventy-one eyes were analyzed in the study. Keraring AS implantation corrected refractive errors significantly. The mean spherical error decreased from -5.06±4.23 D to -1.62±3.45 D (P=0.001), and the mean cylindrical error decreased from -5.43±2.48 D to -2.44±1.49 D (P=0.001). Uncorrected distance visual acuity improved from 0.98±0.80 to 0.46±0.46 Log MAR (P=0.001), and corrected distance visual acuity improved from 0.58±0.56 to 0.17±0.39 Log MAR (P=0.001). Keratometry (K) maximum, K1, K2, K mean, astigmatism, and corneal asphericity (Q-value) showed a significant decrease (P=0.001). Vertical coma aberration decreased significantly from -3.31±2.12μm to -2.56±1.94μm (P=0.001). All topometric indices of corneal irregularities were significantly reduced postoperatively (P=0.001).

CONCLUSIONS

Keraring AS implantation in snowman phenotype keratoconus demonstrated good efficacy and safety. Clinical, topographic, topometric, and aberrometric parameters improved significantly after Keraring AS implantation.

Haze prevention following photorefractive keratectomy in brown eyes

OBJECTIVES

To study corneal haze following myopic photorefractive keratectomy (PRK) in a high-risk population and to assess methods for minimizing the risk.

METHODS

The medical records of 150 patients who underwent PRK were reviewed. A total of 300 eyes were included. All patients underwent myopic PRK using the Allegretto Wave Concerto 500Hz (Wavelight AG, Erlangen, Germany)excimer laser platform with intraoperative mitomycin-C (MMC) application. Demographic data including age, gender and ethnicity in addition to preoperative and postoperative subjective manifest refraction, spherical equivalent, best-corrected distance visual acuity, uncorrected distance visual acuity (UDVA), postoperative corneal haze grade and other possible postoperative complications were retrieved. Hanna grading (0-4+) was used to evaluate corneal haze.

RESULTS

The patients were comprised of 74 men (49.3%) and 76 women (50.7%). The mean age at the time of surgery was 26.5±6.0 (range, 17-46) years. All patients were Saudis with brown irides. UDVA improved to 20/25 in 93.8% at 3 months. The mean and standard deviation of preoperative spherical equivalent was -3.02±1.63 (range, -7.63 - -0.13). At 3 months, postoperative spherical equivalent improved to 0.05±0.50 (-1.00 - +1.00). At 6 months, 13.6% exhibited corneal haze of grade 1, and none exhibited grades 2 or 3.

CONCLUSIONS

The results of this study confirmed that patients with brown irides can achieve favorable outcomes after PRK. MMC, postoperative topical steroids and ultraviolet protection evidently play a major role in preventing corneal haze in high-risk populations.

[Refractive surgery for hyperopia]

Hyperopia is a refractive error in which light is focused behind, instead of on, the retina. Clear vision can be obtained by accommodation, but in the long run, this results in eye strain. Hyperopia can be classified as low [≤2.00 diopters (D)], moderate (2.00-4.00 D) and high (>4.00 D). Detailed preoperative evaluation is necessary and essential to obtain good postoperative results. Various surgical techniques can be proposed to correct this ametropia. The main techniques used act either by modifying the corneal curvature with the Excimer laser or by implanting a phakic intraocular lens. The anatomical peculiarities of the hyperopic eye (small corneal diameter, short axial length, narrow anterior chamber or large kappa angle) make refractive surgery for hyperopia a considerable challenge. Large optical ablation zones now allow correction of high hyperopia by reducing the risks of optical aberrations and regression. The patient must be informed and understand the postoperative course, which differs from that of surgery for myopia.

Excimer laser programming of refractive astigmatism vs. anterior corneal astigmatism in the case of ocular residual astigmatism (ORA)

PURPOSE

To determine whether manifest refractive astigmatism (RA) or anterior corneal astigmatism (CA) is the best value for excimer laser programming in cases of ocular residual astigmatism (ORA).

PATIENTS AND METHODS

Patients who had undergone LASIK surgery with a disagreement between manifest refractive and corneal cylinder (ocular residual astigmatism ORA)>0.75 D were included retrospectively in this study. We calculated target induced astigmatism vector (TIA), surgically induced astigmatism vector (SIA), difference vector between the astigmatism correction programmed in the excimer laser and refractive astigmatism (DVRA), difference vector between the astigmatism correction programmed in the excimer laser and corneal astigmatism (DVCA) and difference vector between TIA and SIA (DV), by the Alpins method. Vectorial differences between DV and DVRA, and between DV and DVCA, were then calculated to determine whether RA or CA was closest to the ideal cylinder for laser programming.

RESULTS

Of a total of 104 eyes undergoing LASIK, 22 eyes of 12 patients (21.1%) had an ORA>0.75 D and were included. Mean ORA was 0.9±0.2 D and mean postoperative subjective cylinder was 0.45 D. The DV-DVRA difference vector was 0.57±0.2 D, and the DV-DVCA difference vector was 0.86±0.4 D (P=0.02). RA was closer than CA to the ideal astigmatism correction.

CONCLUSION

In cases of discrepancy between manifest astigmatism and corneal astigmatism, correction of manifest refractive astigmatism seems to give a better refractive result.

[Corneal topography in practice]

Corneal surface analysis is now more and more accurate. Corneal topography is a gold standard in corneal pathology follow-up: keratoconus, corneal grafts, orthokeratology. In refractive surgery, cornea ectasia post-Lasik must be avoided. Analyzing anterior and posterior surface can detect forme fruste keratoconus FFKC. Topography allows also better predictability of premium intraocular implants surgery. Topography is key examination and its interpretation is essential.

[SMILE (Small Incision Lenticule Extraction) among the corneal refractive surgeries in 2018 (French translation of the article)]

Refractive surgery is a field in constant evolution. In recent years, a new procedure has appeared under the name SMILE (Small Incision Lenticule Extraction). This technique, carried out solely with a femtosecond laser, should make it possible to better preserve corneal innervation and biomechanics. After a detailed review of the technique itself, we then focus on the scientific evidence for the safety and efficacy of SMILE and its current indications. Advantages of SMILE will be discussed in comparison to disadvantages of the conventional techniques, particularly concerning dry eye and the risk of corneal ectasia with LASIK. Lastly, the current limitations of SMILE (indications, retreatment) are discussed, and future applications are considered regarding improvements in the technique.

[Toric lens implantation in cataract surgery: Automatic versus manual horizontal axis marking, analysis of 50 cases]

SUBJECT

The main objective of our study is to evaluate the contribution of automated conjunctival recognition in the alignment of toric implants by comparing the automatic alignment optimized with Callisto™ to the manual marking of the horizontal axis.

MATERIALS AND METHODS

We performed a prospective, descriptive, and monocentric study on patients undergoing cataract surgery with toric implantation (Asphina 709 Zeiss), operated by a surgeon with good experience in toricity, between September 2016 and March 2017. We analyzed the agreement between the manual marking of the 0°-180° axis versus the one automatically generated by the Callisto™, as well as the alignment of the IOL and the refractive results at 1 month.

RESULTS

We included 50 eyes of 26 patients. The corrected mean astigmatism was 1.9 D. The mean difference between the 2 axes was 4.7° [0°-12.3°]. Only 50 % of the preoperative manual markings were consistent with the automatic measurement (<5°). At one month, the average rotation recorded was 4.3° [0°-29°]. The alignment was identical for 70 % (n=35) of the IOL (≤5°). As for residual subjective astigmatism, it was on average 0.58 D. The mean visual acuity without correction was 8/10 and 55 % had 10/10 without correction.

DISCUSSION

The refractive performance depends on the preoperative measurement, the correct alignment of the IOL and its stability in the bag. Our study shows the value of automatic conjunctival recognition in the determination of the axis of peroperative alignment, even in an experienced operator. This precision is essential for a good refractive result, especially since the residual astigmatism in case of misalignment will increase with the power of the implant.

CONCLUSION

Our study shows excellent refractive results, whatever the initial astigmatism, using the automatic alignment. The precision of the toric implantation opens the way to the toric multifocal implantation under the best conditions.

Implantation of posterior chamber phakic intraocular lens for myopia and hyperopia - long-term clinical outcomes

PURPOSE

To evaluate long-term refractive outcomes of implantable collamer lens (ICL) implantation and late postoperative complications.

METHODS

We assessed outcomes of patients who underwent ICL implantation (type ICM V4 for myopia, ICH V3 for hyperopia, TICM V4 for astigmatism) in our department between 1998 and 2013. It comprised 62 eyes (40 myopic and 22 hyperopic). The average follow-up period was 10.5 years. We evaluated: uncorrected and best-corrected visual acuity (UCVA and BCVA), spherical equivalent (SE), ICL vault, endothelial cell density and late postoperative complications.

RESULTS

In myopes, the average UCVA was 1.0±0.37 and BCVA 1.18±0.38, in hyperopes 0.78±0.19 and 1.14±0.18, respectively. The average SE in myopes, whose target refraction was emmetropia, was -0.6±0.83 Dsf, in hyperopes +0.73±0.93. Central ICL vault was 206.16μm±105.94, (range 10-427) in myopes, 195.5μm±109.09, (range 20-404) in hyperopes. The most common late postoperative complication was cataract formation. Three myopic eyes (7.5%) developed symptomatic anterior subcapsular opacities with loss of at least two lines of BCVA. Cataract significantly affecting visual acuity occurred in 5 myopic eyes (12.5%) and 2 hyperopic eyes (9.09%). In these eyes, ICL removal and cataract surgery was performed.

CONCLUSIONS

In our experience, ICL implantation in moderate and high ametropia was effective and relatively safe. The most common late complication was cataract formation. This complication can be managed effectively surgically with good refractive outcomes without loss of BCVA.

[Evaluation of vision quality after laser vision correction in healthcare professionals]

PURPOSE

Healthcare professionals require good quality of vision. The main objective of this study is to evaluate the satisfaction and vision quality after laser vision correction in healthcare professionals.

METHODS

This is a monocentric retrospective study. An online 25-question survey was sent to ametropic physicians, surgeons and nurses who underwent corneal refractive surgery with laser-assisted in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between July 2012 and February 2016. Questionnaire responses were recorded anonymously by the internet survey site. These patients' pre- and postoperative data were analyzed.

RESULTS

In total, 2491 laser vision corrections were performed during this time frame. One hundred and fifty-eight patients were healthcare providers; 131 received the survey, and 111 responded. Ninety-nine were surgeons, 60 were medical physicians, and 32 were nurses. Ninety-one percent reported that they were satisfied with their postoperative vision quality, 63.9% even reported an improvement in their quality of vision compared with their corrected preoperative vision, 92.8% reported that they would have the procedure again, and 94.6% would recommend the procedure to a family member or a patient. Visual outcomes showed high levels of efficacy and predictability.

CONCLUSION

While healthcare professionals require good quality of vision, those who had undergone laser vision correction reported the same satisfaction as the general population and would recommend the procedure to their family, friends and patients.

[The effects of cycloplegic eyedrops on corneal tomography]

PURPOSE

Whether cycloplegics affect standard keratorefractometric and tomographic measurements is unknown. The purpose of our study was to compare the effects of cycloplegics (cyclopentolate and atropine) on corneal shape and refractive power of the eye.

METHODS

This study was performed on 84 eyes of 49 study participants. Patients were randomized into two groups: atropine 1% (32 eyes) and cyclopentolate 1% (52 eyes). Corneal tomography was performed with the Orbscan IIz. To evaluate the corneal shape, simulated keratometry values, anterior and posterior best-fit sphere, white-to-white and tangential and axial corneal power were performed for the anterior and posterior corneal surfaces before and during cycloplegia. Pupil diameter, anterior chamber depth, corneal thickness at the 3, 5 and 7mm optical zones, thinnest area of the cornea and corneal thickness at the visual axis were examined. Data were analyzed using an SPSS statistical package.

RESULTS

The anterior and posterior BFS (in the atropine 1% group, anterior BFS was P=0.188; anterior BFS in the cyclopentolate group was P=0.227) and tangential and axial corneal power showed no change during cycloplegia in either group. SimK showed no statistical significance. The ACD was deeper when using atropine than cyclopentolate. Corneal thickness remained unchanged during cycloplegia in both groups. Pupil diameter was larger in light-colored irides in the cyclopentolate group than the atropine group. There was no change in W to W before (P=0.473) and during cycloplegia (P=0.287) in either group.

CONCLUSIONS

Our results suggest that usage of atropine or cyclopentolate does not alter corneal shape.

[Comparison of two different surgical treatments of presbyopia for hyperopic patients over 55 years old: Presbylasik (Supracor) and Prelex (presbyopic lens exchange)]

INTRODUCTION

The management of presbyopic patients is a medical, surgical and economic issue. We wondered which procedure, whether a Presbylasik technique called Regular Supracor or the intraocular surgery of clear lens replacement by a trifocal diffractive lens (presbyopic lens exchange [Prelex]), provided the best results (in visual acuity and satisfaction) for our hyperopic and presbyopic patients between 55 and 70. The aim of this study was to compare the safety and efficacy of the two techniques (at one week and three months) and to assess patients' quality of life.

METHODS

This study is a retrospective monocentric clinical trial conducted between June 2011 and March 2014, on 21 hyperopic presbyopic patients (mean age 60.9 years), in the "hôpital d'instruction des armées-Percy" (Clamart); 13 patients underwent the corneal treatment of Presbylasik (with the Intralase FS60 femtosecond laser [AMO, USA] and the Technolas 217P excimer laser [Technolas Perfect Vision, GmbH] following the Zyoptix Tissue-Saving algorithm adjusted with a nomogram and the Regular Supracor mode), and 8 patients underwent clear lens extraction (Prelex), through bimanual phacoemulsification and implantation of diffractive trifocal intraocular lenses (Finevision Micro F, PhysIOL(*)).

RESULTS

Mean uncorrected binocular distance and near vision visual acuity in the Supracor group were respectively 0.03 (-0.2-0.1) LogMar and 0.23 (0.06-0.36) one week postoperatively and 0.031 (-0.2-0.1) and 0,166 (0.06-0.36) three months postoperatively. In the Prelex group, the mean uncorrected one week binocular VA was 0.025 (0-0.1) for distance vision and 0.165 (0.06-0.18) for near distance and the three months visual acuity was 0 (-0.1-0.1) and 0.105 (0.06-0.18) for distance and near vision. All Prelex patients were spectacle-free at all distances, whereas 4 Supracor patients required spectacles for near vision postoperatively. Seven of 11 patients in the Supracor group and 100% of the Prelex patients were completely satisfied. Both groups experienced halos, but patients reported more halos in the Prelex group (75%). One eye required intraocular lens exchange and four eyes (16.7%) required a new corneal procedure in the Supracor group.

CONCLUSION

Both surgeries are safe and effective modalities in the management of hyperopic and presbyopic patients. However, the Prelex procedure seems to be more appropriate for patients over 55 years of age.

[Epithelial basement membrane dystrophy diagnosed following LASIK surgery]

A 48-year-old woman with no significant past history underwent bilateral simultaneous laser in situ keratomileusis for correction of her myopia. On the tenth postoperative day, the patient complained of visual decrease and photophobia. Slit lamp exam showed corneal epithelial irregularities. Confocal microscopy was performed and revealed a characteristic appearance of epithelial basement membrane dystrophy (EBMD). The patient was successfully treated with artificial tears and autologous serum eyedrops. EBMD may be missed before LASIK surgery, even after a careful pre-operative examination. Exacerbation of EBMD after LASIK surgery is rare. It should be considered when unexplained corneal epithelial defects or irregularities occur following LASIK. Confocal microscopy is very useful to confirm the diagnosis.