The significance of cone outer segment tips as a prognostic factor in epiretinal membrane surgery.

Abstract

To evaluate the prognostic value of the cone outer segment tips (COST) and other features using spectral-domain optical coherence tomography (SD-OCT) in patients undergoing epiretinal membrane (ERM) surgery. Retrospective observational case series. Fifty eyes of 49 patients that underwent vitrectomy for idiopathic ERM were studied. Best-corrected visual acuity (BCVA) and SD-OCT images were examined preoperatively and at 1 and 6 months postoperatively. The SD-OCT features evaluated included central foveal thickness (CFT) and the status and defect diameter of the external limiting membrane (ELM), the photoreceptor inner/outer segment (IS/OS) junction, and the COST line. The associations between SD-OCT parameters and BCVA were analyzed. There was no ELM disruption found, and thus the eyes were categorized into 3 groups: Group A, with a continuous IS/OS and COST line; Group B, with a continuous IS/OS but disrupted COST line; and Group C, with a disrupted IS/OS and COST line. At 6 months, Group A showed a significantly better BCVA than Group B (P<.005), and poorer BCVA was noted in Group C (P=.034). Defect diameters of IS/OS and COST line were also significantly correlated with BCVA postoperatively. The BCVA at 6 months was better in order of Group A, B, and C as assigned at baseline (P<.05) or 1 month (P<.001). There was no significant correlation between CFT and BCVA. The status of the COST line, in conjunction with the IS/OS junction, is a useful prognostic factor after ERM surgery.