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: Research Ethics Board approved, 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: 100 patients(50 with RRD,50 controls) were included. 70%(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 to 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 ROC 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: We 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 metamorphopsia questionnaire(MeMoQ). A total score of ≥0.2 with M-CHARTS was more strongly correlated with MeMoQ.