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Is it valid to use a mobile app to test a worker’s colour vision?

A quick check of the App Store reveals more than 50 applications (apps) that can be downloaded to a smartphone for testing colour vision. Many of these apps display images similar in concept to the Ishihara Test and could be used by an individual to check if they (or a family member) have a colour vision defect.

Apps may appear an attractive option for pre-employment colour vision screenings for workers. The app is significantly cheaper than purchasing colour vision test books (such as the Ishihara Test), and the app does not suffer the fate of book tests that may fade with time or become discoloured with finger smudges1.

Mobile apps are currently not a valid alternative to colour vision test books. Why?

• Colour vision tests are carefully constructed so they can detect colour vision defects. If a colour is not accurately displayed then a person could pass the test when they actually have a colour vision defect, or fail the test when they have normal colour vision. Commercially available colour vision test books are printed accurately. Even if an app is well designed, the displayed colours can vary between digital devices2, giving different results for the same person.

• Digital devices come in all shapes and sizes, and so the image on the app may be a different size to the plate in the colour vision test book. Size differences can affect the accuracy of the test3.

• The coloured plates in a book are made with pigments and dyes (subtractive colour mixing) whereas the colours displayed on a digital device are made up of light (additive colour mixing). These differences may affect how some colour vision defects are detected4.

Colour vision apps are a quick and easy way to self-test colour vision, but might not always give an accurate diagnosis. For more accurate results, especially for employment testing, it is better to use a genuine colour vision test book under the testing conditions recommended by the test manufacturer.


1. Bodduluri et al (2017) Evaluation of Tablet Computers for Visual Function Assessment. Behavioural Research 49: 548-558

2. De Fez et al (2018) Can Applications Designed to Evaluate Visual Function Be Used in Different iPads? Optometry and Vision Science 95(11): 1054-1063

3. Sorkin et al (2016) Comparison of Ishihara Booklet with Color Vision Smartphone Applications. Optometry and Vision Science 93(7): 667-672

4. Dain et al (2016) Colorimetric evaluation of iPhone apps for colour vision tests based on the Ishihara test. Clinical and Experimental Optometry 99(3): 264-273

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