Comparison of a Smartphone Application with Ishihara Pseudoisochromatic Plate for Testing Colour Vision

Jiawei Zhao, Michael Fliotsos, Mehrnaz Ighani, Allen O. Eghrari

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The Eye Handbook (EHB) is the most frequently downloaded smartphone application with diagnostic tools for eye-care providers. However, limited data exists validating the EHB test to gold standard colour vision testing. EHB and Ishihara colour vision tests were evaluated and compared under simulated colour vision loss through use of image processing software. Images of both tests were processed through ImageJ to 32 bit-grey scale and blue channel under split RBG channel to model total colour vision loss and red-green (R-G) deficiency, respectively. Two colour plates differentiated R-G deficiency from total colour blindness in EHB compared with eight Ishihara plates. Without colour information, correct numerals were identified in 3.5/15 EHB plates converted to 32-bit greyscale, versus 1/16 in Ishihara. We conclude EHB may underestimate colour vision loss severity in persons with normal contrast sensitivity compared to Ishihara. Eye-care providers need to be aware of the potential inconsistency compared to standardised methods, including limitations in differentiating patients with R-G colour deficiencies from total colour blindness.

Original languageEnglish (US)
Pages (from-to)235-239
Number of pages5
Issue number4
StatePublished - 2019


  • Ishihara
  • colour vision testing
  • eye handbook
  • smartphone application

ASJC Scopus subject areas

  • Ophthalmology
  • Clinical Neurology


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