PurposeBased on the assumption that high levels of intraocular pressure (IOP) during femtosecond laser-assisted in situ keratomileusis (FS-LASIK) may compromise the retinal nerve fiber layer (RNFL), newer femtosecond platforms that operate without causing significant IOP elevation have been developed in recent years. However, this assumption has not been adequately tested. The aim of the current study was to evaluate possible changes in RFNL thickness in nonglaucomatous myopic patients undergoing FS-LASIK using the 60 KHz IntraLase® device that significantly elevates the IOP for an appreciable period of time vs an advanced surface ablation technique (laser-assisted subepithelial keratomileusis, LASEK) that does not induce any IOP elevation.MethodsThis was a prospective, observational, controlled cohort study. One randomly selected eye of 114 consecutive eligible patients was analyzed. Inclusion criteria were myopia up to -6.00 diopters and astigmatism up to -2.00 diopters. As clinically indicated, 50 patients underwent LASEK and 64 underwent FS-LASIK. The RNFL thickness was determined with a spectral-domain optical coherence tomography device preoperatively and 3 months postoperatively by the same masked observer.ResultsThere was no significant difference in preoperative refractive error, age, or sex between the groups. Preoperatively, central corneal thickness was significantly lower in the LASEK group (529.1±36.1 vs 562.4±31.6 µm, P=0.001). For the LASEK group, there was no significant difference between preoperative and postoperative RNFL thickness in the studied sectors (superior-temporal, temporal, inferior-temporal, average). For the FS-LASIK group, compared to preoperative RNFL measures, statistically significant thicker postoperative values were found for the average RNFL (mean difference: 0.67 µm, 0.7% increase, P=0.008) and the inferior-temporal sector (mean difference: 0.92 µm, 0.6% increase, P=0.02).ConclusionLASIK with a femtosecond platform that induces high intraoperative IOP did not cause RNFL thinning. The observed differences between preoperative and postoperative values are below the axial resolution limit of optical coherence tomography devices.

Purpose: To describe the incidence, risk factors, and management of pupillary abnormalities after anterior chamber (AC) full air or gas tamponade in Descemet membrane endothelial keratoplasty (DMEK) without pupillary block. Methods: In this retrospective case series, clinical records of 25 patients (32 eyes) who underwent DMEK were reviewed for pupillary abnormalities and iris morphology. All patients had nearly full intracameral tamponade with air or 20% SF6 at the end of surgery without default air release postoperatively. Results: Pupillary abnormalities ranging from mild ovalization to mid-mydriasis were seen in 56% of the cases. These abnormalities were not related to morphometric changes in the iris volume, or in the iris dilator or iris sphincter muscle, but were probably due to posterior synechiae. Combining DMEK and cataract surgery increases by 5-fold the odds of developing this complication. Surgical revision of the posterior surface of the iris and synechiolysis reversed these pupillary abnormalities. Conclusions: Nonischemic pupillary abnormalities can be seen in patients with DMEK using a nearly full air/gas tamponade in the AC after surgery despite patent iridectomy especially when combined with cataract surgery. Ensuring complete mydriasis in the immediate postoperative period and a free-floating bubble in the AC above the inferior pupillary margin may reduce its incidence.

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Measurement of the intraocular pressure elevation during laser-assisted in situ keratomileusis flap creation using a femtosecond laser platform.