Anatomic and functional results of idiopathic macular epiretinal membrane surgery

To assess the impact of macular surgery on the functional and anatomic outcomes in patients with grade 2 epiretinal membrane (ERM), and the effect of internal limiting membrane (ILM) peeling on visual acuity and to analyze the long-term effect of pars plana vitrectomy (PPV) on intraocular pressure (IOP).

Pseudophakic eyes (62 eyes) diagnosed as idiopathic grade 2 ERM with at least 6mo postoperative follow-up were included in this retrospective study. The fellow eye was nonvitrectomized. Patients were divided into two groups: group 1 (29 eyes) treated with ERM and ILM peeling and group 2 (33 eyes) with only ERM peeling. Preoperative and postoperative best corrected visual acuity (BCVA), slit-lamp, and a dilated fundus examination was performed. IOP was measured with Goldman applanation tonometer before, day 1 and first week and each visit after surgery. The incidence of significant IOP elevation was compared between vitrectomized eyes and nonvitrectomized fellow eyes.

Visual improvement was statistically significant and similar in both groups (P=0.008 in group 1, P=0.002 in group 2, P=0.09 inter-group). The amount of decrease in central macular thickness was statistically significant and similar in both groups (P=0.005 group 1, P=0.008 group 2, P=0.37 intergroup). At the final follow-up (14.1±9.6mo) the incidence of significant IOP elevation was 4% in vitrectomized eyes (three eyes) and 3% (two eyes) in the nonvitrectomized fellow eyes (P=0.12). Four eyes (12.1%) had recurrent ERM after a mean follow-up of 8.6±1.1mo in group 2, there was no recurrence in group 1 (P=0.01).

Recurrence of ERM may be decreased by ILM peeling during ERM surgery. However, it seems that ILM peeling do not affect the functional outcome and 23-gauge PPV alone do not have a significant effect on IOP.