Increase in average foveal thickness after internal limiting membrane peeling

Purpose To report the findings in three cases in which the average foveal thickness was increased after a thin epiretinal membrane (ERM) was removed by vitrectomy with internal limiting membrane (ILM) peeling. Methods The foveal contour was normal preoperatively in all eyes. All cases underwent successful phacovitrectomy with ILM peeling for a thin ERM. The optical coherence tomography (OCT) images were examined before and after the surgery. The changes in the average foveal (1 mm) thickness and the foveal areas within 500 μm from the foveal center were measured. The postoperative changes in the inner and outer retinal areas determined from the cross-sectional OCT images were analyzed. Results The average foveal thickness and the inner and outer foveal areas increased significantly after the surgery in each of the three cases. The percentage increase in the average foveal thickness relative to the baseline thickness was 26% in Case 1, 29% in Case 2, and 31% in Case 3. The percentage increase in the foveal inner retinal area was 71% in Case 1, 113% in Case 2, and 110% in Case 3, and the percentage increase in foveal outer retinal area was 8% in Case 1, 13% in Case 2, and 18% in Case 3. Conclusion The increase in the average foveal thickness and the inner and outer foveal areas suggests that a centripetal movement of the inner and outer retinal layers toward the foveal center probably occurred due to the ILM peeling.