Ishihara charts versus tritan blue test in diagnosis of optic neuropathy

Background There are various causes of optic neuropathy (ON). Accurate diagnosis of ON based on clinical history, examination, and investigations. ON generally leads to decreased visual acuity, altered color perception, and visual field (VF) defects in the affected eye. Objective Comparing the accuracy of Ishihara charts and the Tritan (blue) test in detecting early color vision changes in different types of ON. Patients and methods A comparative observational cross-sectional study of 50 eyes with different types of ON. Ishihara charts and Tritan (blue) tests were used to detect early color vision changes in all eyes. Results were compared and reported. Results There was no superiority of the Tritan (blue) test over Ishihara charts in cases of ON, except for glaucoma patients ( P <0.001). The relationship between the nerve fiber layer thickness and Ishihara chart scores in glaucoma patients was insignificant ( P 0.90). Conversely, the relationship between nerve fiber layer thickness and Tritan (blue) test scores in glaucoma patients was significant ( P 0.03). The association between VF changes and Ishihara chart scores in glaucoma patients was insignificant ( P 0.09). The relationship between VF changes and the Tritan (blue) test scores in glaucoma patients was significant ( P 0.01). Conclusion The Tritan (blue) test is more sensitive to detecting color vision deficiency in glaucoma patients than the Ishihara charts. There was no difference between the tests in other cases of ON. The use of Ishihara charts as a first-line color vision test in ophthalmological examinations could be reconsidered.