Comparison between Hardy-Rand-Rittler 4th edition and Ishihara color plate tests for detection of dyschromatopsia in optic neuropathy

Background: The aim of this work was to compare the specificity-sensitivity balance of the Hardy-Rand-Rittler (HRR) 4th edition with the Ishihara color plate tests for color-vision defects in patients with optic neuropathy. Methods: This is a prospective case-control study. The study group included 43 patients (48 eyes) with newly diagnosed optic neuropathy, and the control group included 33 patients (33 right eyes) who were referred to the eye clinic for conditions other than optic nerve or retinal macular disorders. Individuals with visual acuity of less than 20/70 (0.54 Log MAR) were excluded. All patients underwent comprehensive eye examination and color-vision evaluation with both tests in a random order under standardized lighting conditions. The scores of the Ishihara and HRR tests were set as the number of plates identified out of 12 and six respectively. Results: The receiver operating characteristics (ROC) curve was statistically significantly better when using the HRR test (area under curve [AUC] = 0.93 ± 0.03) than for the Ishihara test (AUC = 0.77 ± 0.05) (P = 0.0006). The best specificity-sensitivity balance for the HRR was 100 % and 79 % respectively, and for the Ishihara test 100 % and 48 % respectively. Conclusions: The HRR 4th edition test proved to be superior to the Ishihara test in detecting acquired dyschromatopsia due to optic neuropathy. We recommend using the HRR 4th edition test as a screening method for detection of color-vision defects in patients with optic neuropathy.