Clinical color vision testing and correlation with visual function

Purpose To determine if Hardy-Rand-Rittler (H-R-R) and Ishihara testing are accurate estimates of color vision in subjects with acquired visual dysfunction. Design Assessment of diagnostic tools. Methods Twenty-two subjects with optic neuropathy (aged 18-65) and 18 control subjects were recruited prospectively from an outpatient clinic. Individuals with visual acuity (VA) <20/200 or with congenital color blindness were excluded. All subjects underwent a comprehensive eye examination including VA, color vision, and contrast sensitivity testing. Color vision was assessed using H-R-R and Ishihara plates and Farnsworth D-15 (D-15) discs. D-15 is the accepted standard for detecting and classifying color vision deficits. Contrast sensitivity was measured using Pelli-Robson contrast sensitivity charts. Results No relationship was found between H-R-R and D-15 scores (P =.477). H-R-R score and contrast sensitivity were positively correlated (P =.003). On multivariate analysis, contrast sensitivity (β = 8.61, P <.001) and VA (β = 2.01, P =.022) both showed association with H-R-R scores. Similar to H-R-R, Ishihara score did not correlate with D-15 score (P =.973), but on multivariate analysis was related to contrast sensitivity (β = 8.69, P <.001). H-R-R and Ishihara scores had an equivalent relationship with contrast sensitivity (P =.069). Conclusion Neither H-R-R nor Ishihara testing appears to assess color identification in patients with optic neuropathy. Both H-R-R and Ishihara testing are correlated with contrast sensitivity, and these tests may be useful clinical surrogates for contrast sensitivity testing.