PurposeThe purpose of the study was to determine the accuracy of intraocular pressure (IOP) measurement after small incision lenticule extraction (SMILE) using Goldmann applanation tonometry (GAT) and ocular response analyzer (ORA).MethodsThis is a prospective clinical study that was conducted on 30 eyes in the interval between February 2016 and September 2016. The age of the patients ranged between 19 and 40 years. The patients underwent SMILE surgery using the femto laser. IOP was measured preoperatively and 1 month postoperatively by both techniques, the GAT and the ORA.ResultsGAT recorded lower values than ORA values (IOPcc) preoperatively and postoperatively and the difference was statistically significant. Both GAT and ORA IOP measurements decreased after SMILE. There was no statistically significant correlation between the changes in the GAT and ORA readings and the postoperative corneal pachymetry or the lenticule thickness. Both corneal hysteresis and corneal resistance factor showed significant decline after the procedure, which correlated with the lenticule thickness.ConclusionSMILE causes significant reduction in IOP measurement by ORA and GAT. Corneal biomechanics decreases following SMILE and this correlates with lenticule thickness.
Purpose: To investigate if topography-guided laser in situ keratomileusis (LASIK) depending on the topographic astigmatism which is measured using the Topolyzer leads to a better refractive outcome when compared to treatment of the manifest refractive astigmatism in cases of myopic astigmatism. Methods: This was a prospective non-masked, randomized study (block randomization) of postoperative vision and refraction of patients with myopic astigmatism that had LASIK using Contoura vision software. They were divided into three groups according to the treatment strategy, treating the manifest astigmatism in one group, the topographic astigmatism with compensation for the spherical power in the second group and treating the topographic astigmatism without changing the spherical power in the third group. It was conducted at Kasr Alainy Hospital and Dar Eloyon Hospital. Results: The postoperative uncorrected distant visual acuity (UDVA) in each group separately was better than the preoperative corrected distant visual acuity (CDVA) (58% (n=35) had UDVA better than 20/20 and gained 1 line or more); however, eyes treated with the topographic astigmatism without changing the spherical power showed the statistically best results (75% (n=15) had UDVA better than 20/20). The residual anterior corneal astigmatism was lower in this group (the mean 0.47 vs 0.95 and 0.59). No significant difference was noted in the residual refractive astigmatism, but it was also the least in that group. Conclusion: Topography-guided LASIK is a safe and effective ablation profile for treatment of myopic astigmatism. Treating according to the topographic astigmatism shows the best outcome as regards the vision and residual astigmatism.
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