EnChroma Color Blindness App

As an optometrist, I test children for color blindness on a routine basis, but many adults come in asking me if they might have a color vision problem too.   Have you ever wondered if your color vision is up to snuff?  No surprise, but there is an app for that.  

Sample of the EnChroma screening test via

Enter EnChroma, a smart phone app that is compatible with iPhone, Android, and the Kindle Fire.  The test uses traditional methods -- showing a shape in different colored circles so that only someone with proper color perception can see that shape.  Traditionally the test is done with each eye at a time (but a gross test like you would be taking with a smart phone app at home wouldn't be getting that technical).  

Color blindness is a relatively common phenomenon in our population -- about 8% of men and 0.5% of women are affected (the gene for color blindness is X linked, meaning men are much more susceptible).  Red-green deficiencies are by far the most common problem (which can be further separated into protan or red-weakness and deuteran or green-weakness issues).  Blue-yellow defects are more likely with diseases of the eye, especially macular degeneration that affects blue photoreceptors.  There are only 3 categories of cone photoreceptors in the eye, which means that every color we see is a combination of signals from blue, red, and green receptors.  Strange right, that in the human eye yellow is not a primary color after all.  Some people have more cones devoted to red or green than they should, and thus a color weakness develops.  If you have a ton of cones devoted to red, and not many to green, the color green isn't going to get much of a response when you see it. Thus you have a green-weakness problem, and would be classified as red-green colorblind.

This well-done image tries to depict what a color blind person would see on a Ishihara Color Blindness test
Protanope = no red receptors, Deuteranope - no green, and Tritanope = no blue
via

Optometry jokes are the best 

If you think you have a color blindness issue, or are worried that your child may have one, I think it is no problem to try this app out and test yourself at home.  But if the results worry you, it is always best to consult with a doctor before making any diagnosis for yourself or others.  This test needs proper lighting to give accurate results, so best to have things rechecked properly if you fail the app's screener.

If you do have color blindess, there are many technologies being developed to help you better detect colors around you, including tinted lenses and contact lenses.  Be on the lookout for upcoming posts devoted to this topic!