Corneal flap assessment with Rondo microkeratome in laser in situ keratomileusis

Abstract

To assess the accuracy of flap thickness in laser in situ keratomileusis (LASIK) with Rondo, Wavelight AG microkeratome and to examine factors that can influence flap thickness (FT). The study took place at the Laser & Ophthalmos Eye Clinic, Thessaloniki, Greece. Three hundred and sixty eyes from 180 patients underwent LASIK with Rondo microkeratome. Three surgeons (A, B and C) performed all surgeries with no previous experience of Rondo microkeratome. All patients were treated with the 130μm plate. Central corneal thickness (CCT) and stromal bed thickness were measured by Scheimpflug and ultrasound pachymetry. Right eye (OD) was treated first. Mean FT for OD: 120 ± 19μm (range 69-158μm); for left eye (OS): 106 ± 17μm (range 70-147μm). Flaps in OD were significantly thicker than in OS (p < 0.001). FT was significantly correlated to the keratometric reading (K): r = 0.121; p = 0.02. No correlation was found between FT and CCT or between FT and the attempted refractive correction (SE) (p > 0.14). Mean FT was significantly lower than the manufacturer's 130μm specification (Mean FT = 113 ± 19μm; p < 0.001). FT between surgeons A, B and C was significantly different (analysis of variance between surgeons; p < 0.001). Scheimpflug and ultrasound CCT measurements were significantly correlated (r = 0.921; p < 0.001) with ultrasound measuring an average 4.5μm higher than Scheimpflug (CCT (Oculyzer) = 553.96 ± 27μm; CCT (Ultrasound) = 558.45 ± 28μm). Mean flap diameter was 9.2 ± 0.2mm. FT with Rondo microkeratome was significantly influenced by the mean preoperative K reading. First treated eye was significantly thicker than the fellow left eye, while both were significantly lower than the recommended 130μm thickness. Gaining basic experience of Rondo microkeratome required an average of 90 flaps/surgeon.