Abstract
Purpose :
Extended wear of color correcting lenses (CCLs, www.enchroma.com) improves suprathreshold color perception in hereditary color vision deficiency (CVD) even when CCLs are removed (Werner et al. 2020, doi.org/10.1016/j.cub.2020.05.054). We reported similar results at threshold and suprathreshold levels including cone visual-evoked potentials (VEPs, Rabin et al. 2022, doi:10.1038/s41433-021-01924-0). Our purpose was to further assess VEPs as a metric of CCL efficacy.
Methods :
13 CVDs (9 deuteranomalous, 4 protanomalous, age 32±14,13-66; CVD confirmed by Ishihara, anomaloscope, cone CS) provided informed consent to participate in our initial before-after design. Each subject was given a CCL appropriate for their CVD and tested without and with CCLs at baseline and 11-14 days after wearing CCLs (2.5±1.8 avg. hrs./day). Average cone specific pattern-onset VEPs (Rabin et al. 2016, doi:10.1167/tvst.5.3.8, 1 deg. checks specific to CVD and normal cones) were recorded to 75 pattern onsets without and with CCLs. Data normality allowed for ANOVA and t-tests (Bonferroni correction for multiple comparisons).
Results :
In CVDs immediate wear of CCLs yielded robust VEPs with increased amplitudes (F=8.8, P<.005) and decreased VEP latencies (F=7.2, P<.01) in response to the deficient cone stimulus compared to measures without wearing CCLs. Yet immediate use of CCLs had no effect on amplitude (F=0.2, P>.68) or latency (F=0.6, P>0.43) in response to the stimulus for the CVDs’ normal cone type indicating cone selectivity of this effect. Baseline mean VEP amplitudes for the CVD cone type without CCLs (3.6 µV) was significantly less than mean amplitude with CCLs (6.4 µV, P<.002). Baseline latency without CCLs (119.9 msec) was greater than with CCLs (90.8 msec, P<.02). After 12 days of CCL wear, 67% of CVDs showed increased VEP amplitude without wearing CCLs (mean increase 2.7 µV) and 75% showed decreased VEP latency (mean decrease 38.3 msec), but changes were not significant when compared to baseline measures without CCLs (P>0.38).
Conclusions :
Cone VEPs provide an objective metric of color with use of CCLs. While immediate impact of CCLs on VEPs improved amplitude 2X and decreased latency 30 msec., long term effects occurred in some but not all CVDs, likely due wearing time variations, non-optimal matching of available CCLs to patient needs, and CVD severity. Future studies will include improved CCLs and control measures to address these issues.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.