Inter- and intrasession reproducibility of an open-field portable wavefront autorefractor with and without fogging lenses

Purpose

High repeatability portable autorefractors may enable effective deploy of global-health initiatives to mitigate uncorrected refractive error worldwide. For example, in studies to evaluate the effectiveness of different measures, repeatability has a direct impact on the statistical power and sample size required, while in screening applications, contributes to increased sensitivity and specificity. This work presents a preliminary assessment of the inter- and intrasession repeatability of an affordable autorefractor (QuickSee, PlenOptika Inc) under two separate measurement conditions, with and without fogging lenses.

Methods

6 volunteers (29,8 ± 8,1 years old) were measured at 2 different sessions spaced 1-week. Each subject was tested 6 times per session with the QuickSee, 3 times in standard mode and 3 using a modified version of the device eyecup to allow over-refraction through fogging lenses (+2.0 D). Intersession measurements were spaced 5 minutes apart and the complete alignment procedure was repeated for each measurement. After converting autorefractor readings into power vectors (M, J0, J45), repeatability was evaluated using the Bland-Altman method to compare differences between all possible combinations from each subject (inter- and intrasession). Repeatability coefficients (RPC), estimated as the 95% limits of agreement, and the mean absolute errors were also evaluated. In all cases, only results for the right eyes were analyzed.