EPIRETINAL MEMBRANE IN NONEXUDATIVE AGE-RELATED MACULAR DEGENERATION Anatomical Features, Visual Outcomes and Prognostic Factors

Purpose: To evaluate clinical characteristics, assess surgical outcomes, and determine prognostic factors after vitrectomy for epiretinal membrane (ERM) associated with nonexudative age-related macular degeneration (AMD). Methods: This study comprised 171 consecutive patients with idiopathic ERM (n = 132) or nonexudative AMD-associated ERM (AMD-ERM, n = 39) undergoing vitrectomy. Preoperative morphologic characteristics on spectral-domain optical coherence tomography images and postoperative outcomes of the two groups were compared. Factors influencing postoperative best-corrected visual acuity in the AMD-ERM group were also analyzed. Results: The AMD-ERM group was more likely to have an ERM with a smooth appearance (P = 0.009), a less severe vessel traction score (P = 0.002), a thinner central foveal thickness (P = 0.016), and more photoreceptor disruption than idiopathic ERM group. Mean central foveal thickness improved from 404.92 +/- 82.08 and 369.87 +/- 68.17 mm at baseline to 339.77 +/- 39.27 and 331.72 +/- 45.76 mm 1 year after surgery in eyes with idiopathic ERM and AMD-ERM, respectively (all P < 0.001). Mean logarithm of the minimum angle of resolution best-corrected visual acuity improved from 0.30 (20/40) +/- 0.21 and 0.32 (20/42) +/- 0.18 at baseline to 0.02 (20/21) +/- 0.09 and 0.13 (20/27) +/- 0.17 1 year after surgery in the idiopathic ERM and AMD-ERM groups, respectively (all P < 0.001). Baseline integrity of the ellipsoid zone line (P = 0.009) and preoperative best-corrected visual acuity (P = 0.024) were significantly correlated with visual outcome in the AMD-ERM group. Conclusion: Morphologic differences between AMD-ERM and idiopathic ERM were identified. Vitrectomy resulted in significant anatomical and visual improvements in eyes with AMD-ERM, but final visual outcome was worse in these eyes than in those with idiopathic ERM.