Use of electronic health records to examine margin-to-reflex distance in patients without eyelid conditions affecting position

PURPOSE: To characterize reference margin-to-reflex distance 1 (MRD1) measurements across different demographic factors, age, sex, race, and ethnicity, using a large electronic health record-derived (EHR) dataset. METHODS: This was a single-institution observational, cross-sectional study of adult patients seen in an academic oculoplastics division from October 2018 to June 2023. MRD1 values were extracted from structured data fields and free-text progress notes. Patients with diagnoses known to affect MRD1 (e.g. dermatochalasis, ptosis) were excluded from the study. Univariate analysis was conducted using one-way ANOVA and post hoc testing, while multivariable analysis testing was done through a linear mixed-effects regression model. RESULTS: A total of 6231 patients and 11,932 reference MRD1 values were analyzed. MRD1 decreased by approximately 0.2 mm (mm) per decade of life (p < 0.001). Female sex was associated with higher MRD1 measurements (3.38 vs 3.003, p < 0.001), while Asian race was associated with lower MRD1 values (2.99 vs 3.32, p < 0.001). CONCLUSIONS: MRD1 values vary significantly by age, sex, and race. These findings provide reference values for MRD1 within a clinical oculoplastics population accounting for demographic factors.