SQUARE GRID DEFORMATION ANALYSIS OF THE MACULA AND POSTOPERATIVE METAMORPHOPSIA AFTER MACULAR HOLE SURGERY.

PURPOSE: To investigate the correlation between postoperative metamorphopsia and macular deformation after macular hole surgery. METHODS: This study included 28 eyes of 28 patients who underwent vitrectomy and internal limiting membrane removal for an idiopathic macular hole. The retinal vasculatures were compared between preoperative and postoperative photographs, and postoperative deformation of the macula was assessed as deformation of the square grid. The displacement of each node was measured, and deformation of the grid was calculated as differences in the coordinates of the adjacent nodes. These parameters were analyzed to find correlation with metamorphopsia measured using the M-charts after 6 postoperative months. RESULTS: The average deformations in the vertical and horizontal lines of the grid were 94.29 µm and 49.72 µm, respectively. Perifoveal deformation was significantly greater than parafoveal deformation (P = 0.001∼0.019). The multiple regression analysis demonstrated that the vertical M-score correlated with superior perifoveal deformation of the vertical line on the fovea (P = 0.036), and the horizontal M-score correlated with temporal perifoveal deformation of the horizontal line on the fovea (P = 0.032). CONCLUSION: The parafoveal tissue was displaced with the fovea concurrently after internal limiting membrane removal in macular hole surgery causing perifoveal deformation, which correlated with postoperative metamorphopsia.