Abstract
Purpose :
Congenital red-green color vision deficiency (CVD) affects approximately one in twelve males with deutan CVD being the most common type. The aim of this study was to study the effects of spectral lenses on color detection in patients with congenital red-green CVD.
Methods :
Twelve subjects (4 deutans and 8 controls) participated in the study. Only right eyes’ data were included for analysis. Color vision functions were evaluated at psychophysical level with two methods including Rabin cone contrast test (RCC), HMC anomaloscope test, and at eletrophysiological level with red/green contrast pattern electroretinogram (ERG). All evaluations were conducted under two conditions: with and without the Enchroma filter.
Results :
For the RCC test in deutans without the Enchroma filter, the mean red, green and blue scores were 75, 13 & 100 respectively (94, 92 & 100 in normal controls) with the green score significantly decreased. With the Enchroma filter, the mean red, green and blue scores were 77, 38, & 98 respectively. The mean green score increased significantly by 25% (>15%), while the mean red and blue scores showed no significant change. For the HMC anomaloscope test (Rayleigh match) in deutans without the Enchroma filter, the mean match midpoint and the reference light values were 6.8 and 17.1 respectively (40.3 and 15.1 in normal controls) with the match midpoint value significantly shifting to green (p<0.001), and without significant difference in the reference light value (p=0.02). With Enchroma filter, the mean match midpoint value improved from 6.8 to 21.8 (p=0.01), and the reference light value increased from 17.1 to 30.1 (p=0.001). For the red/green contrast pattern ERG in deutans without the Enchroma filter, the steady-state response amplitude decreased to 0.17 mV (0.50 mV in normal controls) (p=0.29), and increased to 0.23 mV (p=0.72) with the Enchroma filter, although these changes were not statistically significant.
Conclusions :
Deutans show abnormalities in RCC, HMC anomaloscope, and red/green contrast pattern ERG tests. The Enchroma filter significantly improved performance for the green score of the RCC test and shifted the match midpoint of the HMC anomaloscope test. Further study is needed to related these findings to wavelength discrimination.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.