The association between photoreceptor layer thickness measured by optical coherence tomography and visual sensitivity in glaucomatous eyes

PURPOSE To assess the thickness of the photoreceptor layer in the macular region in glaucomatous eyes. METHOD Humphrey 10-2 visual field (VF) testing was carried out and mean threshold (mTH) was calculated in 118 eyes from 118 patients with open angle glaucoma. Macular optical coherence tomography (OCT) measurements (RS 3000, Nidek Co.ltd., Aichi, Japan) were also carried out in all eyes. Thickness measurements were recorded in the outer segment and retinal pigment epithelium (OS+RPE), the nerve fiber layer (NFL), the ganglion cell layer and inner plexiform layer (GCL+IPL), the inner nuclear layer and outer plexiform layer (INL+OPL) and the outer nuclear layer and inner segment (ONL+IS). The relationship between mTH and the thickness of these five different layers was investigated. Additionally, the influence of OS+RPE on mTH was investigated using partial correlation eliminating the effect of other variables of NFL, GCL+IPL, INL+OPL, ONL+IS, age, gender and axial length. RESULTS The thickness of the OS+RPE layer was significantly decreased with the decrease of mTH (coefficient = 0.63 p <0.001). Partial correlation analysis suggested OS+RPE thickness is significantly (coefficient = 0.31, p <0.001) related to mTH, independent from NFL, GCL+IPL, INL+OPL, ONL+IS, age, gender and axial length. CONCLUSIONS The thickness of the RPE+OS layer appears to be related to visual sensitivity in glaucoma.