Free Ishihara Color Blind Test

This scientifically-designed test uses Ishihara plates to screen for red-green color blindness and other color vision deficiencies. The test takes approximately 2-3 minutes to complete.

Before You Begin

  • Ensure your screen brightness is at a comfortable level (not too dim or bright)
  • Take the test in a well-lit room without direct glare on your screen
  • Remove any color-filtering glasses or contact lenses
  • View the screen at arm's length (approximately 60-70 cm)
  • Answer within 5 seconds per plate for best accuracy
  • If you're unsure of an answer, make your best guess

Medical Disclaimer

This online screening test is for educational purposes only and does not constitute a medical diagnosis. Monitor settings and lighting conditions may affect results. For a definitive assessment of your color vision, please consult a qualified eye care professional.

About the Ishihara Color Blind Test

The Ishihara test is the most widely used color perception test for red-green color deficiencies. Developed by Dr. Shinobu Ishihara in 1917 at the University of Tokyo, it has been the standard color vision screening method for over a century.

How the Test Works

The test consists of circular plates (called Ishihara plates) containing a pattern of colored dots. Within these dots, a number or shape is embedded using dots of a different color. People with normal color vision can see the number clearly, while those with color vision deficiencies may see a different number or no number at all.

Types of Plates Used

  • Demonstration plates: Visible to everyone, used to verify understanding
  • Transformation plates: Show different numbers depending on the type of deficiency
  • Vanishing plates: Only visible to those with normal color vision
  • Hidden digit plates: Only visible to those with color vision deficiency

Limitations of Online Testing

While online Ishihara tests can provide a useful screening, they have limitations compared to clinical testing. Monitor color calibration, ambient lighting, and screen quality can all affect results. For occupational or medical purposes, always consult an eye care professional for standardized testing under controlled conditions.

References

  • Ishihara, S. "Tests for Colour-Blindness." Kanehara Shuppan Co., Ltd., Tokyo, 1917.
  • Birch, J. "Diagnosis of Defective Colour Vision." Butterworth-Heinemann, 2001.
  • Cole, B.L. "The handicap of abnormal colour vision." Clinical and Experimental Optometry, 87(4-5), 258-275, 2004.