VALIDATION OF M-CHARTS FOR QUANTITATIVE ASSESSMENT OF METAMORPHOPSIA FOLLOWING RHEGMATOGENOUS RETINAL DETACHMENT REPAIR.

Purpose: To validate the quantitative assessment of metamorphopsia in rhegmatogenous retinal detachment (RRD) using M-CHARTS by determining its correlation with subjective reporting of metamorphopsia with a validated metamorphopsia questionnaire (modified MeMoQ).
Methods: The Research Ethics Board approved a prospective observational study carried out at St. Michael's Hospital, Toronto, Canada. Patients with primary, unilateral RRD and healthy controls were included. Metamorphopsia at 3 months was assessed with modified MeMoQ and M-CHARTS.
Results: One hundred patients (50 with RRD, 50 controls) were included. Seventy percent (35/50) of the RRD group had metamorphopsia with M-CHARTS and 80% (40/50) with MeMoQ. The modified MeMoQ and total M-CHARTS scores were significantly higher in patients with RRD compared with controls ( P < 0.0001). Cronbach's alpha reliability coefficient was 0.934 in the RRD group. Horizontal, vertical, and total M-CHARTS scores were significantly correlated with MeMoQ scores (r s  = 0.465, P = 0.0007; r s  = 0.405, P = 0.004; r s  = 0.475, P = 0.0005, respectively). M-CHARTS was 72.7% sensitive and 94.6% specific for detection of metamorphopsia (positive score ≥ 0.2), with an area under the receiver operating characteristic curve = 0.801. A stronger correlation was found in patients who scored ≥0.2 on the M-CHARTS and reported metamorphopsia with the MeMoQ (r s  = 0.454, P = 0.001).
Conclusion: The authors have validated M-CHARTS as a tool to quantitatively assess metamorphopsia in patients with RRD, which is significantly correlated with patient-reported outcomes using the MeMoQ. A total score of ≥0.2 with M-CHARTS was more strongly correlated with MeMoQ.