Evaluation of Outer Retinal Layer Thickness in Normal and Glaucomatous Eyes using Spectral Domain Optical Coherence Tomography

Abstract

Purpose: The purpose of this study was to examine the outer retinal layer thicknesses in normal and glaucomatous eyes with a Topcon 3D spectral domain optical coherence tomography (SD-OCT) instrument. Methods: Fifty-nine normal eyes and 139 glaucomatous eyes were included in this study. The SD-OCT images were assessed to determine the overall average, superior, and inferior thicknesses of the inner and outer retinal layers. The macula was examined in an area of 7 × 7 mm centered on the fovea and divided into 10 × 10 grids. The thicknesses of the inner and outer macular layers in each square of the ten grids horizontally aligned below the fovea were plotted in a line graph. Results: The findings indicated that all the inner retinal parameters decreased with increasing glaucoma severity. The difference in outer retinal layer thickness between the normal and all the glaucoma groups was not significant. However, the outer retinal layer thickness was significantly different for different glaucoma severity subgroups (P < 0.05). The changes in thickness in the outer retinal layer in the ten small squares horizontally aligned under the fovea revealed significant differences between the normal control group and the various glaucoma severity subgroups. Conclusions: Changes in the thickness of the outer macular retinal layer can be detected using a Topcon 3D SD-OCT 2000. The findings of this study indicate that the outer retinal layer might be involved in glau-