ISHIHARA TEST CHART BOOK

The Ishihara Test Chart Book is a widely used tool to detect color blindness, specifically red-green color deficiencies. It was developed by Dr. Shinobu Ishihara in 1917 and remains the gold standard for assessing color vision.

Key features of the Ishihara Test Chart Book:

1. Design: Each page features a series of plates, usually circular, with colored dots. These dots form numbers or shapes that can be distinguished by people with normal color vision but are difficult or impossible to see for those with red-green color blindness.
2. Types of Tests:
   • Numerical plates: The most common, where individuals are asked to identify the number within the circle of colored dots.
   • Path plates: Some versions include lines or paths that colorblind individuals may have difficulty tracing.
3. Number of Plates: Different versions of the test book exist with varying numbers of plates, ranging from around 14 to over 38 plates for more detailed testing.
4. Purpose: Primarily used for screening red-green color vision deficiencies but not for testing other forms of color blindness like blue-yellow or total color blindness.
5. Usage: It is simple to use, often administered by optometrists, ophthalmologists, or in some workplaces and schools during routine screenings.