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.