Abstract
Purpose :
Color discrimination is an important visual function having functional and occupational implications. We evaluated color discrimination with three different light sources under photopic and mesopic light levels for different age groups using D-15 color discrimination test.
Methods :
Consenting participants with BCVA > 6/9, normal color vision with Ishihara Pseudoisochromatic plates and normal ocular health, aged 18 to 75 years were included. Participants performed the Farnsworth D-15 task at 50 cm in Photopic (800lux) and mesopic (80lux) light levels and with 3 different light types CFL, LED and incandescent light. Time taken to complete an arrangement, Total Error Score (TES), Confusion angle (CA), Confusion index (C-Index) and Selectivity index (S-Index) were calculated for each arrangement of each participant.
Results :
Ninety-two participants with mean age 37.7±14 years were included in 3 age groups (G1: 18-30 years, N=27; G2: 30-45 years, N=41 & G3: >45 years, N=24). Under photopic condition, the TES was significantly (p=0.02) lower for CFL light (12.7±2.8) when compared to LED (13.8±3.3) or Incandescent (14.5±3.4) light sources. The CA (55.1±35.5 deg), C-index (1.2±0.07) and S-index (1.56±0.05) were within normal limits considering all conditions and age groups. Under mesopic condition, the TES was significantly higher (p=0.03) for the incandescent light (15.6±5.2) compared to CFL (13.3±2.9) or LED (13.9±3.6) light sources. Averaging across light sources and age groups, the color discrimination parameters were not significantly different between photopic or mesopic condition (p=0.77). However, the mean time taken to complete the color arrangement was significantly (p=0.006) lower under photopic (177.2 ± 109 sec) than mesopic condition (227±115 sec). Participants in G3 had significantly worser TES (15.8±1.68), S-Index (1.65±0.1), and longer time (234±46.1 sec) for cap arrangement, compared to other two groups. A multifactorial ANOVA of TES revealed significant influence of illuminance level (dF=1, p=0.023), light source (dF=2, p=0.0001) and age (dF=2, p<0.0001), with no significant interactions between the factors.
Conclusions :
Color discrimination was found to be better in CFL or LED light sources. Older participants using Incandescent light source had poorer color discrimination scores. These results could help interpreting clinical color vision tests in an non-standard environment.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.