Fourier-domain optical coherence tomography of eyes with idiopathic epiretinal membrane: correlation between macular morphology and visual function

Purpose The purpose of this study is to evaluate the macular morphological changes associated with idiopathic epiretinal membrane (iERM) using high-resolution Fourier-domain optical coherence tomography (FD-OCT), as they correlate with visual acuity and microperimetry (MP-1). Methods In all, 24 eyes (19 subjects) with iERM were imaged prospectively using FD-OCT with axial resolution of 4.5 mu m and transverse resolution of 10 to 15 mu m. MP-1 and Stratus OCT were carried out in a subset of eyes. Results The mean log of the minimum angle of resolution best-corrected visual acuity (BCVA) was 0.18 +/- 0.16 (range: -0.08 to 0.48, Snellen equivalent 20/15(-1) to 20/ 60). ERM was visualized in all 24 eyes with FD-OCT and in 17 eyes (85%) of 20 eyes imaged with Stratus OCT. Although BCVA correlated with macular thickening in the central 1mm sub-field of the Stratus ETDRS (P = 0.0005) and macular volume (central 3mm area) on FD-OCT (P < 0.0001), macular thickening on thickness map and volume correlated poorly with decrease in macular sensitivity on MP-1 (P 0.16). On FD-OCT, foveal morphological changes correlated best with decrease in BCVA, the strongest being central foveal thickness (P < 0.0001). Other significant changes included blurring of the foveal inner segment-outer segment (IS-OS) junction and/or Verhoeff's membrane, vitreal displacement of foveal outer nuclear layer and foveal detachment (P < 0.05). Foveal IS-OS junction disruption was seen in 25% of eyes on Stratus OCT but in none of the eyes on FD-OCT. Conclusion FD-OCT allowed improved visualization of ERM and associated foveal morphological changes that correlated best with BCVA. Macular thickening correlated weakly with decreased macular function as assessed by MP-1. Eye (2011) 25, 775-783; doi:10.1038/eye.2011.55; published online 25 March 2011