Assessment of the biometric modifications of the eye in LASIK during suction

Abstract

PurposeTo study the biometric modifications of the eyeball during suction in Laser assisted in Situ Keratomileusis (LASIK). MethodsObservational and cross-sectional study. We studied 43 patients who underwent surgery for myopia and myopic astigmatism. Mean age was 38.3 ± 11.5 years, and 19 were female (44.2%). Conventional LASIK surgery with a manual microkeratome was performed. Before and during the suction maneuvre the following parameters were measured using an 11 Mhz biometric probe: aqueous depth (AQD), lens thickness (LT), vitreous cavity length (VCL) and axial length (AXL). Paired t-test was used to compare the biometric measurements before and during suction. ResultsThe mean spherical equivalent refractive error was −4.5 ± 2.3 diopters. During suction, the AQD did not change significantly (p = 0.231). However, AXL and VCL increased by 0.12 mm and 0.22 mm respectively (p = 0.039 and <0.01) and LT decreased by 0.20 mm (p < 0.01). AXL increased in 42% of the eyes and decreased in 16%, VCL increased in 70% of the eyes and decreased in 9%, and the LT was reduced in 67% of the eyes. ConclusionsSuction maneuvres during LASIK surgery produce changes of little magnitude in the eye globe, mainly a decrease in LT and an increase in VCL and AXL. Therefore, these modifications are expected to produce minimal anatomic alterations.