New Tablet-Based Written Examination System for Metamorphopsia Quantification

Background: We aimed to develop a tablet-based written examination system (Implementing digitization in assessment for metamorphopsia: IDAM) to quantify metamorphopsia severity and monitor changes after treatment in patients with epiretinal membrane (ERM) and central serous chorioretinopathy (CSC). Methods: This prospective study included 33 eyes from 31 patients with ERM or CSC. Patients used a tablet and stylus to illustrate perceived line distortions with IDAM. IDAM displayed a grid at a size of 20° × 20° (771 × 771 pixels), and patients depicted any distortions that they perceived in the presented lines. Metamorphopsia scores were calculated by summing the line deviation distances. Scores and distortion areas were compared before and three months after treatment. Results: Thirty eyes had baseline metamorphopsia on IDAM. The average pretreatment IDAM scores were 196,598 pixels (ERM) and 98,414 pixels (CSC). IDAM and M-charts scores were correlated (r = 0.38, p = 0.03). IDAM scores improved post-treatment in both groups (both p < 0.001). Distortion areas decreased from 6.6 to 4.2 (p = 0.0049). Conclusions: IDAM allowed quantitative metamorphopsia evaluation and detected treatment responses. This tablet-based system could facilitate at-home monitoring in macular disorders.