Study of foveal avascular zone by OCTA before and after idiopathic epiretinal membrane removal

The aim of this study was to determine the size of the foveal avascular zone (FAZ) by optical coherence tomography angiography (OCTA) after surgery for an idiopathic epiretinal membrane (ERM).

This study comprised a retrospective, observational case series. In all, 17 eyes of 17 patients with an idiopathic ERM were studied. Pars plana vitrectomy was performed with internal limiting membrane (ILM) peeling. The area of the superficial FAZ and the central macular thickness were determined by OCTA. Retinal sensitivity was measured by microperimetry.

The size of the preoperative FAZ was difficult to determine because of the poor images of the capillary network. The size of the FAZ was smaller than that of the control eyes at all time points (p < 0.001). There was a significant inverse correlation between the area of the postoperative FAZ and the CMT (r = −0.480, p = 0.048 at 3 months; r = −0.565, p = 0.018 at 6 months; r = −0.534, p = 0.027 at 12 months), and between the area of the FAZ and retinal sensitivity (r = −0.622, p = 0.008 at 3 months; r = −0.578, p = 0.015 at 6 months), postoperatively.

The significantly small FAZ after ERM surgery indicates a macular deformity caused by a contraction of the ERM. This change persisted for at least 12 months after the surgery.