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Purpose: To assess variations in the biomechanical properties and central corneal thickness (CCT) throughout the female menstrual cycle., Setting: Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin Israel., Design: Case series., Methods: Young healthy women were prospectively recruited. Every participant was assessed at the beginning of the menstrual cycle, at ovulation, and at the end of the cycle. At every time point, corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured with the Ocular Response Analyzer and the CCT was measured with an ultrasonic pachymeter., Results: Twenty-two eyes of 22 women (mean age 19.5 years ± 1.5 [SD]) were included. The CH was statistically significantly decreased at ovulation (10.1 mm Hg) compared with the beginning (11.1 mm Hg, P<.001) and the end (11.4 mm Hg, P<.001) of the cycle. The CRF was also significantly decreased at ovulation (9.8 mm Hg) compared with the beginning (10.6 mm Hg, P<.001) and the end (10.5 mm Hg, P<.001) of the cycle. The central cornea was thinnest at the beginning (535 μm) and statistically significantly thicker at ovulation (542 μm, P<.001) and at the end of the menstrual cycle (543 μm, P<.001)., Conclusions: The CCT and biomechanical parameters significantly varied during the menstrual cycle. The CH and CRF were temporarily decreased at ovulation. The cornea was thinnest at the beginning and thicker at ovulation and at the end of the cycle. Such corneal changes may be important to consider during screening of candidates for laser refractive surgery., (Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare parameters of biomechanical response of the human cornea measured as corneal hysteresis (CH) and corneal resistance factor (CRF) in patients with diabetes mellitus and healthy control subjects., Setting: Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin, Israel., Methods: In the right eye of each participant, the CH, CRF, Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) were measured with the Ocular Response Analyzer. Central corneal thickness (CCT) was measured by ultrasonic pachymetry and intraocular pressure by Goldmann applanation tonometry (IOP GAT). Findings were compared between the 2 groups (control and diabetic)., Results: Forty diabetic patients (17 women, 23 men) and 40 healthy subjects (19 women, 21 men) were prospectively recruited. The mean CH was 9.3 mm Hg +/- 1.4 (SD) and 10.7 +/- 1.6 mm Hg and the mean CRF was 9.6 +/- 1.6 mm Hg and 10.9 +/- 1.7 mm Hg in the control group and diabetic group, respectively (both P < .0001). Diabetic corneas were significantly thicker (P = .019); the mean CCT was 530.3 +/- 35.9 microm in the control group and 548.7 +/- 33.0 microm in the diabetic group. The CH and CRF remained significantly different in multivariate analysis that included CCT. There was no statistically significant difference between the 2 groups in IOPcc, IOPg, or IOP GAT measurements., Conclusions: Diabetes mellitus affected biomechanical parameters of the human corneas, including increased CH, CRF, and CCT. Whether this observation has implications in the clinical management and understanding of corneal ectasia and glaucoma requires further study.

Purpose: To study the distribution of ocular higher-order aberrations (HOAs) in a myopic population and to assess the repeatability of HOA measurements determined by a commercially available skiascopic wavefront sensor., Setting: Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin, Israel., Methods: Ocular HOAs were examined 3 times across a 6.0 mm naturally dilated pupil in 61 eyes using the Optical Path Difference (OPD)-scan wavefront aberrometer. Root-mean-square (RMS) values of HOAs, total spherical aberration (TSA), total coma (TC), and total trefoil (TT) were analyzed. Correlation analysis was performed to assess the aberration symmetry between right and left eyes. The repeatability of the OPD-scan measurements was assessed by calculating Pearson r correlation coefficients between each pair of measurements and the interclass correlation coefficients between the 3 measurements of each score., Results: The mean RMS values of HOAs, TSA, TC, and TT were 0.347 microm +/- 0.252 (SD), 0.120 +/- 0.174 microm, 0.165 +/- 0.168 microm, and 0.252 +/- 0.157 microm, respectively. The HOAs, TSA, TC, and TT changed slightly and not significantly with increasing refractive error (all P>.05). The RMS level of HOAs and TTR of the 3rd measurement was significantly different from the 1st and 2nd measurements (P<.05), with overall low correlation between the 3 measurements for the HOAs, TSA, TC, and TT., Conclusions: The ocular wavefront aberrations varied greatly from subject to subject. Ocular HOAs were not correlated with refractive error. The repeatability of HOAs measurements with the OPD-aberrometry was low.

Purpose: To evaluate the outcome of excimer laser phototherapeutic keratectomy (PTK) for recurrent corneal erosion., Setting: Laser Institute, Assay Harofeh Medical Center, Zerifin, Israel., Methods: Twenty-three patients with a mean age of 50.56 years +/- 13.87 (SD) were referred between 1991 and 1995 for recurrent corneal erosion that did not respond to conservative treatment. All were treated by excimer laser PTK. Patients were interviewed and examined before and after treatment., Results: Disease duration ranged from 2 months to 10 years. Frequency of attacks ranged from weekly to three to four times a year. Re-epithelialization of the cornea was established within an average of 3 days after PTK treatment. Follow-up was 12 to 60 months (mean 38.43 +/- 12.08 months). Nineteen (83%) patients were free of recurrences, and 3 had one recurrence treated successfully by patching. One patient who had two recurrences had a second PTK procedure and was symptom free for 14 months. No patient reported reduced visual acuity or quality. Postoperative best corrected visual acuity was unaltered in 21 eyes and improved in 2. There was no significant difference between preoperative and postoperative manifest refractions., Conclusion: Excimer laser PRK appears to be a safe and effective treatment for recurrent erosions of the cornea.