Displacement of the retina and changes in the foveal avascular zone area after internal limiting membrane peeling for epiretinal membrane.

Abstract

We investigated the differences in displacement of the outer and inner macular retina toward the optic disc after vitrectomy with internal limiting membrane (ILM) peeling for epiretinal membrane (ERM). Foveal avascular zone (FAZ) area changes were also investigated. Retrospective observational study METHODS: This retrospective observational case series included 45 eyes of 43 patients that underwent vitrectomy with ERM and ILM peeling for ERM and 38 normal eyes. The locations of the centroid of the FAZ (C-FAZ, center of the foveal inner retina) and foveal bulge (center of the foveal outer retina) were determined using 3×3mm superficial optical coherence tomography angiography. C-FAZ and foveal bulge displacements, and the pre- and postoperative FAZ areas and their associated factors, were investigated. Postoperative C-FAZ dislocated significantly more toward the optic disc than in pre-operative or normal eyes (P<0.001). C-FAZ and foveal bulge displaced toward the optic disc after surgery; C-FAZ showed significantly greater displacement than foveal bulge (P<0.001). The pre- and postoperative FAZ areas were correlated (P=0.01). Preoperative FAZ areas ≧0.10mm2 were reduced after surgery, and FAZ areas < 0.10mm2 were increased, independent of foveal displacement. ILM peeling during vitrectomy for ERM caused larger displacement of the inner and smaller displacement of the outer retinas, towards the optic disc. Postoperative changes in the FAZ area were dependent on the baseline FAZ area, but not on the foveal displacement. ILM may physiologically exert centrifugal tractional forces on the fovea.