Ishihara Color Blindness Test
The Ishihara color vision test is the global benchmark for screening red-green color deficiencies. Consisting of pseudoisochromatic dot plates, each plate conceals numerals or geometric paths discernible through intact cone photoreceptor cells.
Ishihara Color Blindness Clinical Test
View the plates from 50–70 cm in even ambient lighting. Do not squint. If no number is visible, select 'Nothing'.
How to use
- Sit approximately arms-length (50-70 cm) from your monitor in natural ambient light.
- Examine each color dot plate for 3-5 seconds without squinting.
- Identify the hidden number or figure among the colored circles.
- Input your answer or select the matching option.
- Ensure device night mode, true-tone, and blue light filters are deactivated.
- Review your comprehensive results breakdown.
Methodology & Optical Principles
Pseudoisochromatic plates use random dot matrices matched for lightness and saturation, differing solely in hue chromaticity.
It effectively screens for protanopia (red deficiency), protanomaly, deuteranopia (green deficiency), and deuteranomaly.
Digital Screen Disclaimers
Color reproduction varies across LCD, OLED, and uncalibrated consumer screens. This online test serves as an informative screening tool, not a clinical ophthalmologic diagnosis.
Frequently Asked Questions
What does the Ishihara test assess?
It assesses the functioning of the L-cones (long-wave / red) and M-cones (medium-wave / green) in the human retina.
What do errors on specific plates indicate?
Missing specific plates indicates potential red-green color vision deficiency (protan or deutan axis).
How common is color blindness?
Red-green color blindness is an X-linked recessive trait affecting approximately 8% of biological males and 0.5% of females.
Does this test provide a medical diagnosis?
No. Formal diagnostic evaluation requires physical standardized print plates under certified daylight illumination administered by an eye specialist.
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