Elimination of a False-Negative Result With the M-CHARTS Metamorphopsia Assessment Tool Achieved Through Sampling Oblique Axes.

Standard implementation of the M-CHARTS metamorphopsia tool presents patients with only vertical and horizontal lines, potentially overlooking distortions not occurring within those precise meridians. The authors propose rotating the M-CHARTS testing booklet about the central fixation point until maximal distortion is perceived, after which sequential M-CHARTS testing can take place along that same axis. In a symptomatic patient with residual parafoveal fluid cysts after release of vitreomacular traction, M-CHARTS testing yielded standard testing scores of 0 (false-negative); upon rotating the reference test line, a score of 0.3 was measured at the 30° meridian. The authors believe this modification of the original methodology is more sensitive and more accurately reflects the severity of a patient's distortions. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:734-736.].