Macular migration toward the optic disc after inner limiting membrane peeling for diabetic macular edema

PURPOSE To investigate the papillofoveal distance and its association with retinal thickness on optical coherence tomography (OCT) images after vitrectomy for diabetic macular edema (DME). METHODS In this retrospective case series, 72 eyes of 57 consecutive patients who underwent vitrectomy for DME were included. Retinal images dissecting the fovea horizontally were obtained using OCT before and after vitrectomy. After identification of the disc margin and the presumed foveal center, the papillofoveal distance was measured on the OCT images. The association of the distance with retinal thickness and peeling of the inner limiting membrane (ILM) was evaluated. RESULTS The papillofoveal distance was significantly shorter after vitrectomy (3956.1 ± 299.0 μm vs. 3759.6 ± 331.3 μm; P < 0.001), and the shortening was correlated negatively with the total and inner retinal thickness in the temporal subfield (r = -0.29, P = 0.012 and r = -0.34, P = 0.004, respectively). Shortening of the papillofoveal distance was greater in 54 eyes in which ILM peeling was performed compared with 18 eyes in which ILM peeling was not performed (234.7 ± 159.3 μm vs. -9.7 ± 83.5 μm; P < 0.001). No differences were seen in the papillofoveal distance and retinal thickness before and after surgery between eyes with and without preoperative epiretinal membrane or posterior vitreous detachment. The total and inner thicknesses in the temporal subfield were thinner postoperatively in eyes that underwent ILM peeling than those without ILM peeling (P < 0.001 and P < 0.001). CONCLUSIONS The papillofoveal distance on OCT images was shortened and the retina in the temporal subfield was thinner in eyes that underwent ILM peeling to treat DME.