Effect of EnChroma glasses on color vision screening using Ishihara and Farnsworth D-15 color vision tests

Abstract

Background: The prevalence of color vision deficiency (CVD) is about 0.5% in females and 8% in males. Although there is no cure for CVD, specially filtered glasses are purported to improve color contrast. One recent development is the EnChroma filter. The purpose of this study was to assess the effect of the EnChroma filter on color vision screening (CVS) using Ishihara and Farnsworth D-15 color vision tests.

Methods: The medical records of patients with CVD were reviewed retrospectively. Responses to color vision testing with and without the EnChroma filter were evaluated using Ishihara and Farnsworth D-15 tests, and the overall scores were analyzed.

Results: A total of 38 eyes of 19 patients were included. Mean error scores of no filter compared to EnChroma were significantly reduced in 17 eyes using the Ishihara test (0.88 ± 0.03 vs 0.85 ± 0.03, P = 0.017). The error score significantly reduced only in deutans (P = 0.022), not in protans (P = 0.44). The confusion index of no filter to the EnChroma filter was significantly reduced in 20 eyes using the Farnsworth test (3.30 ± 0.15 vs 2.98 ± 0.17; P = 0.01). The confusion index significantly reduced only in protans (P = 0.01), not in deutans (P = 0.19).

Conclusions: In this study cohort, the EnChroma filter significantly reduced overall error scores using the Ishihara and Farnsworth tests; error scores on Ishihara testing reduced only in deutans. Conversely, the confusion index using Farnsworth reduced only in protans. The majority of patients reported subjective increase in color perception.