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Purpose: To evaluate the refractive outcomes of small-incision lenticule extraction (SMILE) surgery in moderate to high myopic astigmatism., Study Design: Prospective interventional case series., Methods: This study evaluated 111 eyes of 68 patients treated with femtosecond SMILE surgery for the correction of myopia and astigmatism. Inclusion criteria were myopia of - 0.5 D or more and astigmatism between - 1.0 D and -5.0 D. Refractive and visual measurements were obtained preoperatively, 1 and 12 month(s) postoperatively. Vector analysis was used to study the astigmatic outcomes at 12-month follow-up. Comparison of results in two groups of patients with astigmatism below and over 3.00 D was performed., Results: The preoperative mean spherical equivalent was -5.48 ± 2.17 D (range - 1.75 to - 10.00 D) and the mean cylinder was -2.02 ± 1.09 D (range - 1.00 to - 5.00 D). The mean postoperative cylinder value was -0.60 ± 0.52 D at 12-month visit. The 12-month safety and efficacy indices were 0.98 ± 0.07 and 0.97 ± 0.12, respectively. The high astigmatism group showed significantly lower safety and efficacy indices. The postoperative residual astigmatism was 0.5 D or less in 73% of the eyes. Higher amount of residual astigmatism was observed in the high astigmatism group. The angle of error was ± 5 degrees in 49% and ± 15 degrees in 87% of the eyes., Conclusion: SMILE surgery is effective and safe method for correcting myopic astigmatism. Vector analysis indicated a tendency for the under correction of astigmatism in subjects with high astigmatism.

Purpose: To investigate the change in anterior, posterior, and net corneal power more than 18 months after photorefractive keratectomy (PRK) by RTVue anterior segment optical coherence tomography (OCT)., Setting: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran., Design: Prospective observational study., Methods: PRK was performed using Technolas TENEO 317 laser platform. Anterior, posterior, and net corneal power was measured by the RTVue-XR anterior segment OCT system with the Pachymetry + Cpwr scan pattern at baseline and months 1, 3, 6, 12, 18, and more than 18 (up to 27) after PRK., Results: Three hundred twenty-six eyes of 163 patients (61 men [37.4%], 102 women [62.6%]; mean age 29.71 years; range 18.5 to 46.5 years) were enrolled in this study. Mean preoperative spherical equivalent was -3.15 ± 1.50 diopter (D) (range -8.37 to -0.62 D). The mean change in net corneal power was 3.052 D, 3.281 D, 3.324 D, 3.114 D, 3.446 D, and 3.972 D at months 1, 3, 6, 12, 18, and more than 18 postoperatively compared with baseline, respectively (P < .001 for all comparisons). The mean change in posterior corneal power at postoperative visits compared with baseline was not statistically significant (P > .1) except for 1 month postoperatively, which increased by 0.13 D (P < .001). Changes in posterior corneal power were not correlated with any of the preoperative clinical and Scheimpflug variables., Conclusions: Posterior corneal power did not change for more than 18 months after PRK, except for an early small increase at 1 month postoperatively.

Purpose: To assess the effect of two silicone hydrogel contact lenses with high oxygen permeability in patients having photorefractive keratectomy (PRK)., Setting: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran., Methods: Sixty patients (120 eyes) who had bilateral PRK were enrolled in this double blind clinical trial. Each patient was fitted with a Lotrafilcon B (Air Optix(®)AQUA, Ciba Vision, Duluth, GA, USA) lens in one eye and a Balafilcon A (PureVision™ Bausch & Lomb, Rochester, NY, USA) lens in the fellow eye. Patients' responses to a subjective questionnaire in terms of pain, foreign body sensation, photophobia, blurred vision and epiphora were evaluated on the first and third postoperative days., Results: Mean pain score for Lotrafilcon B and Balafilcon A contact lenses was 4.43±3.18 vs. 5.45±3.37 on the first postoperative day and 3.43±3.23 vs. 3.88±3.01 on the third postoperative day. However, the difference was only significant in the first 24h after surgery (P=0.032). Foreign body sensation was clinically higher with Balafilcon A contact lens (5.0±3.47 vs. 4.08±3.34 on day 1 and 4.98±3.52 vs. 3.55±3.20 on day 3) and the difference was statistically significant on the first and the third postoperative days (P=0.042 and 0.002, respectively). There was no statistically significant difference between two contact lenses in terms of photophobia, epiphora and blurred vision (P>0.05)., Conclusion: The Lotrafilcon B lens resulted in significantly less postoperative pain and discomfort after PRK, especially in the first 24h after PRK., (Copyright © 2015. Published by Elsevier Ltd.)

Purpose: The aim was to compare the corneal curvature and power measured with a corneal topographer, Scheimpflug camera, optical biometer, and Javal keratometer., Materials and Methods: A total of 76 myopic individuals who were candidates for photorefractive keratectomy were selected in a cross-sectional study. Manual keratometry (Javal Schiotz type; Haag-Streit AG, Koeniz, Switzerland), automated keratometry (IOL Master version 3.02, Carl Zeiss Meditec, Jena, Germany), topography (TMS4, Tomey, Erlangen, Germany), and Pentacam HR (Oculus, Wetzlar, Germany) were performed for all participants. The 95% limits of agreement (LOAs) were reported to evaluate the agreement between devices., Results: The mean corneal power measurements were 44.3 ± 1.59, 44.25 ± 1.59, 43.68 ± 1.44, and 44.31 ± 1.61 D with a Javal keratometer, TMS4-topographer, the Pentacam and IOL Master respectively. Only the IOL Master showed no significant difference with Javal keratometer in measuring the corneal power (P = 0.965). The correlations of the Javal keratometer with TMS4-topography, Pentacam, and IOL Master was 0.991. 0.982, and 0.993 respectively. The 95% LOAs of the Javal keratometer with TMS4-topography, Pentacam, and IOL Master were - 0.361 to 0.49, -0.01 to 1.14, and - 0.36 to 0.36 D, respectively., Conclusion: Although the correlation of Pentacam, TMS4-topography, IOL Master, and Javal keratometer in measuring keratometry was high, only the IOL Master showed no significant difference with the Javal keratometer. The IOL Master had the best agreement with Javal keratometry.

Purpose: To evaluate the effect of MyoRing implantations (DIOPTEX GmbH, Linz, Austria) in patients with ectasia after LASIK., Methods: MyoRing implantation was performed in 15 eyes of 14 patients with ectasia after LASIK using a femtosecond laser. Uncorrected and corrected distance visual acuity, refraction, keratometry, central corneal thickness, corneal biomechanical profile, and corneal aberrometry were evaluated preoperatively and at 1, 3, and 6 months, and 1 year postoperatively., Results: Uncorrected distance visual acuity (1.02 ± 0.48 to 0.30 ± 0.18 logMAR), maximum keratometry (50.14 ± 1.82 to 43.80 ± 1.21 diopters), and sphere (-4.4 ± 4.8 to +1.50 ± 0.61 diopters) were significantly improved from preoperative values at 1 month after surgery with no significant change afterward. Corrected distance visual acuity did not improve significantly 1 month after implantation, but between the 1- and 3-month follow-up visits, a significant improvement (0.30 ± 0.1 to 0.17 ± 0.13 logMAR) was observed without any additional improvement thereafter. A nearly significant (P = .05) increase in central corneal thickness (439.4 ± 19 to 452.2 ± 20 μm) was observed during the 1-month postoperative period. Primary coma, higher-order aberrations, and trefoil showed an insignificant decrease 1 month after surgery and afterward. Spherical aberration significantly increased between the preoperative visit and the first postoperative visit. Corneal hysteresis and corneal resistance factor showed no significant change between visits., Conclusions: MyoRing is a safe and effective method in patients with ectasia after LASIK. It can improve corrected distance visual acuity and reduce refractive error in these patients., (Copyright 2014, SLACK Incorporated.)

Purpose: To assess the effect of mitomycin-C (MMC) on the tear film, corneal biomechanics, and surface irregularity in surface ablation (photorefractive keratectomy [PRK]) for low to moderate myopia., Setting: Refractive Surgery Unit, Farabi Eye Hospital, Tehran, Iran., Design: Double-masked randomized clinical trial., Methods: In patients with spherical equivalent myopia of -0.75 to -3.87 diopters (D) and astigmatism up to -1.75 D, the first eye was randomly assigned to the application of MMC 0.02% or a balanced salt solution for 15 seconds. The fellow eye received the alternate in a masked fashion after excimer photoablation., Results: The study enrolled 60 patients. In fellow eyes, the changes in the tear-film index were comparable 1 month and 6 months postoperatively. There was no significant difference in changes in total higher-order aberrations, spherical aberration, coma, or Q values (Pentacam HR) between fellow eyes at 1 month and 6 months. There was a trend toward a higher asymmetry index at 1 month; however, a statistically significant drop was observed at 6 months in the MMC group (P<.01). It was hypothesized that stromal remodeling was delayed, but better, in MMC-treated eyes. No haze was recorded at 6 months in either group., Conclusion: Use of MMC in PRK did not appear to contribute significantly to surface irregularity, transient tear-film dysfunction, or biomechanical weakening of the cornea compared with PRK without MMC., Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned., (Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the efficacy, predictability, safety, contrast sensitivity, higher-order aberrations (HOAs), and patient satisfaction after tissue-saving photorefractive keratectomy (PRK) and conventional PRK., Setting: Department of Ophthalmology, Farabi Eye Hospital, Tehran Medical University, Tehran, Iran., Design: Comparative case series., Methods: This prospective study evaluated eyes with low to moderate myopia that had PRK with a Technolas 217z excimer laser. Patients were randomly assigned to have surgery using a conventional algorithm (PlanoScan) or a tissue-saving algorithm (Zyoptix). Contrast sensitivity, HOAs, and patient satisfaction were analyzed preoperatively and 1, 3, and 6 months postoperatively., Results: The conventional group comprised 42 eyes (21 patients) and the tissue-saving group, 62 eyes (31 patients). At 6 months, all eyes in both groups were within ±0.50 diopter of the attempted correction and had an uncorrected distance visual acuity of 20/25 or better. However, the tissue-saving group had a statistically significantly greater increase in the mean root mean square of total HOAs and more induced spherical aberration than the conventional group (P<.05). There was no significant difference between the 2 groups in mesopic or photopic contrast sensitivity. The level of satisfaction after surgery was the same in the 2 groups., Conclusions: Although the conventional and tissue-saving algorithms for PRK were both safe and effective in treating low to moderate myopia, tissue-saving PRK induced a greater increase in HOAs than conventional PRK; this may be because of the smaller blend zone of the tissue-saving algorithm. Contrast sensitivity and patient satisfaction were comparable between the 2 methods., (Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)