Comparison of a Smartphone-Based Method for Measuring Anterior Chamber Depth with Anterior Segment OCT and Smith's...

Background: Measurement of anterior chamber depth (ACD) is an important screening method for angle-closure glaucoma risk. We aimed to determine the precision and agreement of a smartphone-based method for measuring ACD when compared with anterior segment optical coherence tomography (AS-OCT) and Smith's technique. Methods: A total of 43 participants (22 female, 21 male) were recruited. The mean age ± standard deviation of participants was 21.9 ± 2.1 years (range = 19-27 years). Three measurements were taken on each participant's right eye in a random order for each technique. For this comparative study, differences in ACD, test-retest variability of a given method, and Bland-Altman level of agreement were computed to compare differences in performance between all three methods. Results: Smith's technique over-estimated ACD, while smartphone photography under-estimated ACD, when compared to the reference AS-OCT. There was proportional bias between all three techniques. Smith's technique had the largest degree of variability, whereas there was no statistically significant difference in test-retest variability between AS-OCT and smartphone photography. Conclusions: Zamir's smartphone photography technique could be used for measuring ACD. Although there are some limitations compared to other established approaches, smartphone photography may have potential as a low-cost screening tool for estimating ACD in settings where specialised equipment is not available. Further studies are required to establish diagnostic performance for angle-closure screening in clinically relevant populations.