Exploring reduction of prolonged binocular vision testing time: the agreement between the first and second thirty seconds within one minute of accommodative and vergence facility tests.

Abstract

Purpose: The study sought to compare the number of cycles (NOS) for the first and second thirty-seconds (FASTS) within 1 min of accommodative facility (AF) and vergence facility (VF) testing to explore possibilities of reducing testing time to 30 s. Methods: In this cross-sectional study, a multistage sample of school children (aged 8-17 years) was taken through ocular-visual screening. Eligible participants (586) underwent refraction, stereo-acuity measurement, AF testing using ± 2D lens flippers, and VF testing using 3^Δ BI/12^Δ BO flipper prisms. The NOS within the FASTS of AF and VF tests were compared, respectively. Results: A statistically insignificant mean difference of 0.01 cycles was found between the NOS for the FASTS of monocular AF in the right eye (Wilcoxon Signed Rank test, p = .715). Statistically significant differences of 0.06, 0.14, and 0.09 cycles (Wilcoxon Signed Rank test, p < .05) which are not clinically meaningful were found for monocular AF in the left eye, binocular AF, and VF with no level of agreement on Bland Altman analysis, respectively. There were no clinically meaningful differences between the first 30-s cycles multiplied by two (FTSMT) and the full 1-min test period cycles for monocular AF, binocular AF, and VF. Conclusion: The FTSMT approach may be applied during gross screening to shorten testing time as further study is recommended for its diagnostic validity.