Abstract
Purpose :
Ocular dominance is the degree to which one eye contributes more than the other when integrating binocular inputs. It can be measured by a variety of tests, and the precision of different ocular dominance tests varies. A novel ocular dominance test has been proposed that involves the dichoptic presentation of letters with opposite contrast polarities (the letter test) (Bossi et al., 2017, 2018). We compared the reliability of this test to that of a binocular rivalry test (the grating test) commonly used in the literature.
Methods :
39 adults with normal vision completed three measurements using both the letter test and the grating test. Each ocular dominance test was administered once per day. To assess within-test repeatability, an intraclass correlation (ICC) analysis was performed across these three measurements, and a Wilcoxon signed-rank test was used to examine any differences in the standard deviations of each test. 7 additional adults with normal vision completed one measurement using both ocular dominance tests. To assess between-test agreement, a Bland-Altman test and an intraclass correlation analysis were performed on the first measurement of all participants (n = 46). The agreement of ocular dominance direction (which eye was dominant) between tests was also assessed.
Results :
For within-test repeatability, an ICC analysis indicated moderate to good repeatability for both the letter test (ICC 95% confidence interval 0.730-0.899) and the grating test (0.674-0.875). The letter test (median standard deviation 0.015) showed less variability compared to the grating test (median 0.023) (Z = 2.414, p = 0.015).
For between-test agreement, both tests produced comparable data for the majority of participants as shown by the Bland-Altman test, with 80.43% data points falling within the ±0.06 acceptable range. Both tests had moderate to good agreement (ICC 95% confidence interval 0.535-0.829). In addition, ocular dominance directions by both tests agreed for 85% of participants.
Conclusions :
The letter test proposed by Bossi et al. is reliable and produces similar ocular dominance results to the grating test. This letter test is suitable for ocular dominance measurement.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.