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To compare the accuracy of three devices (Pentacam, Sirius and OPD-Scan III) to differentiate subclinical keratoconus from normal corneas by wavefront parameters. Two hundred and seventeen patients were enrolled in three groups [68 normal, 79 subclinical keratoconus (SKCN) and 70 KCN eyes] in this prospective diagnostic test study. Wavefront indices were evaluated between the groups using Pentacam, Sirius and OPD-Scan III. The accuracy of the parameters was determined by measuring the area under the receiver operating characteristic curve (AUC) for each group. Front Baiocchi-Calossi-Versaci (BCV) index with Sirius (sensitivity = 87.7%, specificity = 83%, AUC = 0.887), front Vertical Coma (Z3−1) with Pentacam (sensitivity = 75%, specificity = 100%, AUC = 0.857) and Corneal Z3−1 with OPD-Scan III (sensitivity = 100%, specificity = 78.6%, AUC = 0.857) had the highest AUC values for the diagnosis of subclinical KCN. In the KCN group, the highest AUC values were obtained for front higher-order aberration (HOA), front/back Z3−1 and front Secondary Vertical Coma (Z5−1) with Pentacam (sensitivity = 100%, specificity = 100%, AUC = 1.00 for all three), front root mean square values per unit area (RMS/A), HOA, Residual HOA, BCV, RMS Trefoil and RMS Coma with Sirius (sensitivity = 100%, specificity = 100%, AUC = 1.00 for all) and Corneal HOA, RMS total Coma and Z3−1 with OPD-Scan III (sensitivity = 100%, specificity = 93%, AUC = 0.96 for all three). Corneal wavefront indices generated from different devices have acceptable validity for differentiating normal cornea from the early form of KCN, and this can be very useful for preoperative screening before refractive surgery. The front BCV with Sirius was the most accurate parameter for diagnosis of SKCN followed by Z3−1 with Pentacam and OPD-Scan III.

PurposeTo determine the two-year results of small incision lenticule extraction (SMILE) for correcting post-keratoplasty myopia and myopic astigmatism.MethodsIn this case-series study, 10 eyes of 10 patients with a 6-10-year history of successful deep lamellar keratoplasty (DALK) underwent SMILE using VisuMax laser platform. Ophthalmologic examinations and visual acuity and refraction measurement were done pre- and 1, 3, 6, 12, and 24 months postoperatively. Pentacam and Sirius imaging was done in the first and last follow-up session.ResultsThe mean age of the patients was 39.60±7.86 years. Six subjects were male. After two years, uncorrected distance visual acuity did not change in one eye and improved 1-6 lines in other eyes. Corrected distance visual acuity decreased in one eye, did not change in four eyes, and improved 1-8 lines in other eyes. The mean decrease of spherical equivalent, spherical error, and cylinder power was 1.92±1.96 diopter (D) (P=0.013), 0.70±3.05D (P=0.213), and 2.42±2.91D (P=0.024), respectively. The vector mean target induced astigmatism, surgical induced astigmatism, and difference vector was 1.30D@44˚, 1.11D@24˚, and 0.86D@73˚, respectively. Two years after surgery, vertical coma, horizontal coma, and spherical aberration increased by 0.44±0.51, 0.23±0.32, and 0.02±0.16µm respectively (all P>0.05) while trefoil reduced by 0.29±0.75µm (P=0.428).ConclusionSMILE is a successful procedure for reducing refraction and astigmatism after DALK in patients with moderate myopia and moderate to severe astigmatism and improves the visual acuity in these patients. Axis rotation during surgery may result in under-correction of astigmatism. Refinement of SMILE treatment nomogram for post-DALK cases seems necessary.

Purpose: To evaluate diurnal variations in intraocular pressure (IOP), central corneal thickness (CCT), and macular and retinal nerve fiber layer (RNFL) thickness in diabetic patients and normal individuals. Methods: This study included 11 diabetic patients with macular edema and 11 healthy individuals. IOP, CCT, and macular and RNFL thickness were measured every 3 hours on a single day between 9 AM and 6 PM. Diurnal variations in IOP, CCT, total macular volume (TMV), central macular thickness (CMT), average macular thickness (AMT), and RNFL thickness were measured. Results: None of the parameters showed a significant absolute or relative change over the course of the day. However, the following non-significant changes were observed. In the control group, all parameters demonstrated the highest values at 9 AM. The lowest IOP, TMV and AMT occurred at 12 PM; lowest CCT and RNFL at 6 PM; and the lowest CMT at 3 PM. Diabetic subjects had the highest values of RNFL, CMT and TMV at 9 AM, and that for IOP, CCT and AMT at 6 PM. The lowest RNFL and CMT values occurred at 6 PM; lowest IOP at 12 PM; and the lowest CCT, TMV and AMT were observed at 3 PM. In the diabetic group, TMV, CMT, AMT and CCT were significantly higher and RNFL was significantly lower than the control group at all time points (all P- values < 0.05). Conclusion: While there were slight decreases in IOP, RNFL thickness and CMT during the day, these changes were not significant between 9 AM and 6 PM and probably do not affect the interpretation of measurements.