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

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.