Monday, May 25, 2015

Advanced Color Vision test - Do Farnsworth Munsell 100 hue test online

Colorblindess is usually checked in most settings by the Ishihara chart -  a book containing 32 to 38 test plates with colored dots arranged in the shape of a number in a circle.

If you are not colorblind, you shoud see 29


Take an online Ishihara test here :
Ishihara test is designed to diagnose only Protanopia and Deuteranopia - 2 types of Red-Green Color Blindness. It can also pick up Protanomaly and Deuteranomaly - partial color blindess of the red-green variety.

Ishihara's test cannot detect Tritanopia(Blue-Yellow color blindness) and other forms of colour blindness. It also doesn't give any quantification of the defect.

These online tests may also not be very accurate, but they can atleast be used for screening for color blindness.

Sometimes, we need to use another test to quantify the degree of color blindness. There are several tests for this. But the most common one reproduced online is the Farnworth-Munsel 100 hue test. Or the shorter 15-hue test.

Here you are supposed to arrange coloured blocks in the order of color. Once that is done, the software calculates a score based on the position you arranged the blocks in.

A score less than 70 suggests color blindness. This test also gives the result in a spectrum across all the colors so that we can diagnose all the variations of color blindness like tritanopia. It also gives a quantitative value on the degree of colorblindness.

A real world Farnworth-Munsel 100 hue test

A shorter version is the D-15 or 15 hue test.
Here is a Farnworth Munsell 15-color arrangement test online. It is fast and easy but doesn't give much information.

Here are some longer 100 hue Farnswoth-Munsell tests



This site gives a bunch of color tests based on Silverlight(Microsoft's answer to Flash). It is available for Windows phones too. Use it in case you have Silverlight installed already. They have a separate test for tritanopes.

Previously, it was thought that there is no cure for colorblindness except gene therapy. 
Recently, there have been special glasses like EnChroma and Oxy-Iso which help to overcome the color blindness. Read about their comparison here.

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