Validity and acceptance of color vision testing on smartphones

Background: Ishihara color plates (ICP) are the most commonly used color vision test (CVT) worldwide. With the advent of new technologies, attempts have been made to streamline the process of CVT. As hardware and software evolve, smartphone-based testing modalities may aid ophthalmologists in performing more efficient ophthalmic examinations. We assess the validity of smartphone color vision testing (CVT) by comparing results using the Eye Handbook (EHB) CVT application with standard Ishihara color plates (ICP). Methods: Prospective case–control study of subjects 18 years and older with visual acuity of 20/100 or better at 14 inches. The study group included patients with any ocular pathology. The color vision deficient (CVD) group was patients who failed more than 2 plates. The control group had no known ocular pathology. CVT was performed with both ICP and EHB under standardized background illuminance. Eleven plates were tested with each modality. Validity of EHB CVT and acceptance of EHB CVT were analyzed. Statistical analyses were performed using Bland–Altman plot with limits of agreement (LOA) at the 95th percentile of differences in score, independent samples t tests with 95% confidence interval (CI), and Pearson x² tests. Results: The Bland–Altman plot showed agreement between correct number of plates in EHB and ICP for the study subjects (bias, 20.25; LOA, 21.92 to 1.42). Agreement was also observed between the correct number of plates in EHB and ICP for the controls (bias, 20.01; LOA, 20.61 to 0.59) and CVD (bias, 20.50; LOA, 24.64 to 3.64) subjects. The sensitivity of EHB was 0.92 (95% CI 0.76–1.07) and the specificity of EHB was 1.00 (95% CI 1.00–1.00). Fifty-nine percent preferred EHB, 12% preferred ICP, and 29% had no preference. Conclusions: In healthy controls and patients with ocular pathology, there was an agreement of CVT results comparing EHB with ICP. Overall, the majority preferred EHB to ICP. These findings demonstrate that further testing is required to understand and improve the validity of smartphone CVT in subjects with ocular pathology.