Application of Second-Generation Swept-Source Anterior Segment-OCT in the Measurement of Marginal Reflex Distance-1 (MRD-1)

PURPOSE: To measure marginal reflex distance-1 (MRD-1) values in normal subjects and patients with blepharoptosis using second-generation swept-source anterior segment optical coherence tomography (AS-OCT) and to evaluate the usefulness of this measurement method. MATERIALS AND METHODS: MRD-1 values were measured using AS-OCT in 80 eyes of 40 normal subjects (16 men and 24 women) aged 20–59 years with no neurological or endocrinological disorders, and the measured values were compared between four age groups comprising 20 eyes of 10 subjects each in their 20s, 30s, 40s, and 50s. The Volk Eye Check system was simultaneously used to measure MRD-1 in 40 eyes of 20 normal subjects, and the measured values were compared with those obtained using AS-OCT. In 21 eyes of consecutive 13 involutional blepharoptosis patients (48–84 years of age, mean 70.2 years), MRD-1 values were measured using AS-OCT preoperatively and 3 months after surgery to examine the rates of successful measurements as well as preoperative and postoperative results. RESULTS: The mean MRD-1 value using AS-OCT in 80 eyes of 40 normal subjects was 3.70 ± 0.10 mm, whereas the values in 20 eyes of 10 subjects each from the four different age groups were 4.01 ± 0.54 mm, 3.88 ± 0.60 mm, 3.96 ± 0.77 mm, and 2.94 ± 0.79 mm for subjects in their 20s, 30s, 40s, and 50s, respectively; significant differences were observed between the 50s group and other groups (p<0.01). The mean MRD-1 values using AS-OCT and the Volk Eye Check system in 40 eyes of 20 normal subjects were 3.68 ± 0.70 mm and 3.71 ± 0.84 mm, respectively, with no significant differences (p:0.87). The mean preoperative and postoperative MRD-1 values in patients with involutional blepharoptosis were 0.29 ± 0.70 mm and 3.24 ± 0.92 mm, respectively; the rate of successful MRD-1 measurements using AS-OCT was 100% among trial subjects. CONCLUSION: MRD-1 measurement using AS-OCT is a simple and reproducible method that allows the direct comparison of numerical values in normal subjects as well as in patients with blepharoptosis.