Outer retinal morphology and visual function in patients with idiopathic epiretinal membrane.

OBJECTIVE To determine the relationship between the morphology of the fovea and visual acuity in patients with an untreated idiopathic epiretinal membrane (ERM). METHODS We examined 52 eyes of 45 patients diagnosed with an ERM. The morphology of the foveal area was determined by spectral-domain optical coherence tomography. The relationships between the best-corrected visual acuity (BCVA) and 8 optical coherence tomography features, central retinal thickness, cone outer segment tip (COST) line, photoreceptor inner/outer segment (IS/OS) junction line, foveal bulge of the IS/OS line, external limiting membrane, inner limiting membrane, foveal pit, and ERM over the foveal center, were evaluated. RESULTS Multiple regression analysis showed that intact COST line, IS/OS junction line, and external limiting membrane independently and significantly contributed to the BCVA. The standardized partial regression coefficient β was 0.415 for the COST line, 0.287 for the IS/OS junction line, and 0.247 for the external limiting membrane. However, the other features, eg, foveal bulge, inner limiting membrane, foveal pit, and ERM, were not significantly associated with the BCVA. The central retinal thickness was significantly correlated with the BCVA (r2=0.274; P< .01). CONCLUSIONS At an early stage of an ERM, only the photoreceptor structures are significantly associated with the BCVA, and the appearance of the COST line was most highly associated. Detailed examinations of the photoreceptor structures using optical coherence tomography may help find photoreceptor dysfunction in cases of idiopathic ERM.