Analysis of the ganglion cell layer and photoreceptor layer using optical coherence tomography after idiopathic epiretinal membrane surgery.

Abstract

To investigate the correlation of visual acuity with the ganglion cell layer and the photoreceptor layer using spectral-domain optical coherence tomography after surgery for idiopathic epiretinal membrane (ERM). The medical records of 58 eyes were reviewed retrospectively to collect data on visual acuity (VA), ganglion cell complex thickness (GT) and photoreceptor reflectivity (PR) at baseline, 3 months, and 6months after surgery. The GT was adjusted to compensate for tractional thickening by calculating the proportional thickness to the macular thickness (MT). The PR was adjusted to compensate for the shadowing effects from the inner retina, which was achieved by calculating the ratio to the retinal pigment epithelium reflectivity (RR). The relative GT (RGT = GT/MT) and relative PR (RPR = PR/RR) were analyzed to determine their correlation with visual acuity. The GT was segmented correctly in 13 eyes at baseline, and in all eyes after surgery. The RGT and RPR were significantly lower than the normal eye. Thinner RGT correlated with poorer VA at 3 months (R = -0.352, p = 0.007) and 6months (R = -0.324, p = 0.013), but the RPR had correlation with visual acuity only at 6months (R = -0.377, p = 0.004). The area under the receiver operating characteristic curve was significant for VA ≥ 20/30 in both the RGT and RPR, and this significance was present for visual acuity ≥ 0/25 only in the RGT. The postoperative ganglion cell layer was found to be correlated to postoperative VA more consistently than the photoreceptor layer after ERM surgery. The outer retinal damage was a determining factor in the poor VA group.