Digital Color Vision Testing in Optic Neuropathy: Are Smartphone Apps Ready for Clinical Use?

BACKGROUND: Color vision impairment is a common feature of optic neuropathy, typically assessed with the printed Ishihara booklet. Smartphone-based alternatives are increasingly used, but their diagnostic performance in optic neuropathy is incompletely established. METHODS: In this prospective, single-center diagnostic study, 77 participants (42 healthy trichromats and 35 patients with unilateral optic neuropathy of various etiologies) completed 3 monocular color vision tests in a randomized order: a 17-plate Ishihara booklet, the PseudoChromatic ColorTest (PCCT) smartphone application, and the Eye Handbook (EHB) smartphone application, all administered on an iPhone 8 Plus under standardized illumination and viewing distance. The primary outcome was diagnostic accuracy (area under the receiver operating characteristic curve [AUC]); secondary outcomes were correlations of test performance with best-corrected visual acuity and visual field mean deviation and participants' test preference. RESULTS: All 3 tests significantly differentiated healthy from optic neuropathy eyes (P < 0.001). The PCCT achieved the highest AUC (0.812), followed by the EHB (0.778) and the Ishihara booklet (0.736), with no statistically significant between-test differences. Test performance correlated significantly with visual acuity and visual field mean deviation, but not with age. Test preference differed significantly between groups (P = 0.004), with healthy participants favoring app-based testing. CONCLUSIONS: Smartphone-based color vision tests demonstrated overall discriminatory performance similar to that of the printed Ishihara booklet for detecting optic neuropathy, with the PCCT achieving the highest diagnostic accuracy. They may serve as practical screening tools, particularly in tele-ophthalmology and resource-limited settings; independent validation of each application is required before clinical implementation.