Retinal Tectonics after Macular Pucker Surgery: Thickness Changes and en Face Displacement Recovery

Purpose: To study visual function, retinal layer thickness changes, and tangential displacement after pars plana vitrectomy for epiretinal membrane.Methods: Retrospective series of patients undergoing pars plana vitrectomy for epiretinal membrane, with 6-month follow-up including best-corrected visual acuity, optical coherence tomography, M-charts, epiretinal membrane grading, and infrared fundus photograph at time 0 (T0, preop) at months 1 (T1), 3 (T3), and 6 (T6) postop (+/- 1 week). Retinal layer thickness and tangential ( en face ) retinal displacement between successive times for the entire retinal surface and the central horizontal and vertical meridian were also measured. En face displacement was calculated as optical flow of consecutive images.Results: Average best-corrected visual acuity improved from 0.28 +/- 0.08 logarithm of Minimum Angle of Resolution at T0 to 0.16 +/- 0.25 at T6 ( P = 0.05), best-corrected visual acuity improvement correlated with best corrected visual acuity (BCVA) at T0 ( P < 0.001). Vertical metamorphopsia decreased from 1.33 degrees +/- 0.70 degrees at T0 to 0.82 degrees +/- 0.69 degrees at T6 ( P < 0.05). Foveal thickness reduced from 453 +/- 53 mu m at T0 to 359 +/- 31 mu m at T6 ( P < 0.05) and reduction correlated with best-corrected visual acuity improvement ( P < 0.05). Foveal layers decreased ( P < 0.05) in all cases. The mean en face deformation was 155.82 +/- 50.17 m and mostly occurred in the first month: T0-T1 displacement was 83.59 +/- 30.28 mu m, T1-T3 was 36.28 +/- 14.45 mu m, while T3-T6 was 39.11 +/- 22.79 mu m ( P < 0.001) on average. Perifoveal and parafoveal deformation correlated with optical coherence tomography foveal thickness reduction at all time intervals (1, 3, and 6 months: P < 0.01).Conclusion: Epiretinal membrane peeling affects all retinal layer thickness and results in new force balance across the entire retina and tangential displacement. Both en face and in-depth changes correlate with visual function.