Role of ganglion cell complex in visual recovery following surgical internal limiting membrane peeling

PURPOSE:To investigate the Ganglion Cell Complex (GCC) thickness change and visual recovery correlation after surgery for an idiopathic epiretinal membrane (ERM).METHODS:In this prospective, observational, case control study 30 eyes underwent vitrectomy for idiopathic ERM. We analysed best-corrected visual acuity (BCVA), mean macular thickness and mean GCC thickness one day before surgery, seven days and six months after surgery. Internal segment/outer segment junction, external limiting membrane, cone outer segment tips defects and intraretinalfluid were also investigated throughout the follow-up.RESULTS:Baseline GCC thickness was higher in patients with ERM (130 ± 13 μm) compared with healthy eyes (94 ± 5 μm; p < 0.0001). GCC thickness decreased after surgery to 89 ± 11 μm (p < 0.0001), reaching a value similar to controls (p = 0.12). Preoperative macular thickness was 318 ± 32 μm and decreased to 281 ± 18 μm (p < 0.0001), remaining significantly higher than controls (260 ± 8 μm; p < 0.0001). The GCC proportion of the whole macular thickness was also reduced six months after surgery (p < 0.0001). Post-operative BCVA gain showed direct correlation with GCC reduction (R = 0.67, p < 0.0001), but did not correlate with the mean macular thickness reduction (R < 0.01, p = 0.97).CONCLUSIONS:Ganglion cell complex thickness is higher in eyes with idiopathic ERM, and after surgery turns back to similar values of healthy eyes. Post-operative GCC reduction is proportionally higher than thinning of the whole retina, and this reduction is correlated with visual restoration.