Purpose: To propose a novel approach for automated measurements of margin reflex distance (MRD) using digital image analysis and to evaluate the agreement between automated and manual measurements of MRD. Materials and Methods: This observational study included 132 eyes of 66 volunteers referred to an oculoplastic clinic for blepharoptosis. Preoperative facial photographs of participants were taken. MRD1 and MRD2 were measured manually by a senior surgeon and automatically by our image-based algorithm. Correlation analyses and Bland-Altman analyses were performed to evaluate the agreement between the two measurements. Results: A strong positive correlation was observed between automated and manual MRD1 measurements, with Spearman's r = 0.968 (95% confidence interval [CI] = 0.949-0.976; P < .001) and intraclass correlation coefficient (ICC) = 0.966 (95% CI = 0.953-0.976; P < .001). The bias between automated and manual MRD1 measurements was 0.02 mm (95% CI = -0.06-0.10 mm), with 95% limits of agreement (LoA) = -0.88 to 0.92 mm. Agreement also existed in MRD2 measurements, with Spearman's r = 0.803 (95% CI = 0.716-0.865; P < .001), ICC = 0.833 (95% CI = 0.772-0.879; P < .001), and bias = 0.34 mm (95% CI = 0.26-0.42 mm), 95% LoA = -0.54 to 1.22 mm. Conclusions: Automated eyelid measurements in blepharoptosis using the image-based approach compare favorably with clinical manual measurements. This novel approach allows an objective assessment of ptosis with high accuracy.
Keywords: Blepharoptosis; automated measurement; image analysis; margin reflex distance.