Temporal Retinal Thickness in Eyes With Glaucomatous Visual Field Defects Using Optical Coherence Tomography

Abstract

To evaluate the temporal macular retinal thickness in normal, early, and advanced glaucomatous eyes using optical coherence tomography 3 (OCT-3) and correlate the superior-to-inferior retinal thickness (S/I RT) ratio with corresponding field defects in early and advanced glaucoma patients. Forty normal eyes, 40 eyes with early glaucomatous visual field defects, and 33 eyes with advanced visual field defects were included. All participants underwent complete ocular and visual field examinations and OCT-3 imaging on the same day. A 3×3 mm area temporal to the foveal reflex was scanned with the OCT-3 using 6 horizontal, equally spaced raster lines. Retinal thickness was evaluated at points 500 μm apart for each line and S/I RT ratio computed between similar points above and below the fovea for each patient. One-way ANOVA was used to compare S/I RT ratio between the normal, early, and advanced glaucoma eyes. Average retinal thickness increased progressively, as points temporal to the fovea were scanned. There was a statistically significant difference between the average superior and inferior retinal thickness at points 1500, 2000, and 2500 μm temporal to the fovea in both early and advanced glaucoma eyes (P<0.05) with corresponding significant differences in the S/I RT ratios, when compared with the normal participants (P<0.017). OCT-3-generated S/I RT ratios were successfully able to reproduce the structural damage in eyes with early and advanced glaucoma field defects and can complement optic disc scanning protocols in diagnosing glaucoma at an early stage.