Correlation between Metamorphopsia and Epiretinal Membrane Optical Coherence Tomography Findings

Purpose: To examine the retinal morphologic features of metamorphopsia caused by epiretinal membrane (ERM) and to determine whether spectral-domain optical coherence tomography (SD-OCT) correlated with metamorphopsia. Design: Retrospective case series. Participants: This study included 19 eyes of 19 patients with ERM diagnosed by clinical ophthalmic findings and SD-OCT. Methods: The 19 eyes were classified into 3 groups based on Amsler chart results: no metamorphopsia (n 4), local metamorphopsia (n = 8), and broad metamorphopsia (n = 7). The thickness of the 3 inner retinal layers: inner nuclear layer (INL), outer plexiform layer (OPL), and outer nuclear layer (ONL), on 5 horizontal SD-OCT cross-sections (1 line through the fovea, 2 regularly spaced lines superior to the fovea, and 2 regularly spaced lines inferior to the fovea) were measured using the electronic calipers of the SD-OCT system. Main Outcome Measures: Correlation between INL, OPL, and ONL thickness with metamorphopsia and visual acuity. Results: Metamorphopsia was detected in the same position as edematous areas of the INL with a thickness >50 mu m. The maximum INL thickness was relatively significantly different between the subjects with no metamorphopsia and those with local or broad metamorphopsia (vs local, P = 0.06; vs broad, P = 0.04). Visual acuity significantly correlated with both maximum INL thickness (A = -0.681; P = 0.001) and maximum ONL thickness (A = -0.708; P<0.001) in metamorphopsia. Conclusions: Metamorphopsia induced by ERM maybe related to the edematous areas of the INL detected with SD-OCT. The classification of ERM based on INL thickness is a potentially useful indication for surgery. Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article. Ophthalmology 2009,116:1788-1793 (C) 2009 by the American Academy of Ophthalmology.