A new method for quantification of metamorphopsia in patients with epiretinal membrane.

PURPOSE A new method for quantification of metamorphopsia was applied to study distorted vision in patients with epiretinal membrane. METHOD Sixty-three patients with unilateral epiretinal membrane in the macula were examined. A modified Amsler chart (a grid of black lines on a white background measuring 12 x 12 cm with grid squares of 2 x 2 cm) was prepared. If patients saw any of the grid lines as irregular or curved, they were asked to trace these on the chart. The length of all lines drawn by the patients was measured, except those on the outer border. The length of the grid is 1200 mm, but it should be drawn longer by patients with metamorphopsia. The severity of metamorphopsia was also scored subjectively and the relationship of grid length to the subjective score and the visual acuity was analyzed. RESULTS The grid length ranged from 1200 to 1259 mm (mean = 1223.3 mm) and was correlated significantly with the subjective score (P <.01, rho =.387). CONCLUSION This method might be applicable for evaluating the severity of metamorphopsia and the surgical outcome in patients with epiretinal membrane.