Nerve fibre layer changes in highly myopic eyes by optical coherence tomography

Abstract

Objective: The purpose of this study was to investigate any correlations that may exist between retinal nerve fibre layer (RNFL) thickness and high myopia by optical coherence tomography (OCT). Design: Case-control study. Participants: Ten patients (20 eyes) with high myopia and 10 control patients (20 eyes) matched for age and sex were recruited from a database search of 1 vitreoretinal practice in Regina, Sask. Methods: The RNFL thickness of 10 highly myopic patients and 10 control patients matched for age and sex from a clinical practice was determined using the Stratus OCT. All 10 highly myopic patients selected for the study had a spherical equivalent of ≥−10.0 D OU and an intraocular pressure <21 mm Hg OU, and failed to display glaucomatous changes such as disc hemorrhages and glaucomatous cupping in either eye. None of the patients included in the study had evidence of concomitant ophthalmic disease and none had had previous refractive surgery. Axial length measurements were done on all patients using the IOL Master. Results: The mean (SD) RNFL thicknesses in the control and myopic groups were 108.8 (10.6) μm and 80.0 (18.6) μm, respectively, with t = 6.0 and p − 0.001. A negative correlation of −0.712 with p < 0.001 was found between RNFL thickness and axial length. Conclusions: When interpreting the RNFL thickness of highly myopic patients by OCT, careful attention must be given to the inherently thinner RNFL to avoid a false glaucoma diagnosis.