Eye health and computers continue to become better and better friends. It’s true, computers cause a lot of issues for the eyes – CVS is becoming a major problem in the digital era – but technology is evolving to help diagnose many common vision problems.
One of the more recent developments: digital tests designed to screen for color blindness. Older, physical methods have been functional, but come along with some basic deficiencies that have hustled computer-based models into the foreground.
What is Color Blindness?
“Blindness” is generally an overstatement. Color blindness is a catch all term that covers an enormous number of disorders, ranging from rare total insensitivity to color to much more common “weakness” in perceiving certain hues.
All together, those many forms affect a surprising number of people. Roughly 7-10 percent of males are color blind in one way or another, while women are – for genetic reasons – very, very rarely affected. For men of European descent, that number is even higher.
By far the most common variety is red-green color blindness. People with the disorder can generally see a fairly wide range of tones. However, some (with a condition called protanopia) see extremely muted versions of red, orange, and yellow, making it difficult to distinguish or even perceive those shades. Others (individuals with deuteranomaly, the most common form) don’t have problems with brightness, but are considered “green-weak” and have trouble perceiving green in low light, as well as difficulties telling some colors apart.
Causes of Color Blindness
Just about all cases of color blindness have a genetic root. Relatively small abnormalities in the X chromosome inherited from an individual’s parents can affect cones, the cells in the eye responsible for perceiving color. This heritability also explains why women aren’t as susceptible. Females have two X chromosomes as opposed to just one for men – if one X chromosome is deficient, a second one can generally take up the slack. In the normal eye, three types of cones are present, referred to as blue, green, and red cones. Although they aren’t strictly limited to the colors suggested by their names, these cells allow humans to have the full range of “trichromatic” color vision.
Mutations can tamper with pigments in those cells, shifting vision toward a different neutral point and making it difficult to tell colors apart. Or, they can result in only a fraction of those cones being manufactured to begin with. Color blind individuals may have three cone varieties, or two, one, and in extremely rare cases none at all, causing total color blindness.
Diseases, including Parkinson’s, macular degeneration, and diabetic retinopathy can also cause color blindness through direct damage to the visual system. Head injury is another possible culprit, though symptoms may not appear until years later.
Effects of Poor Color Vision
Most color blind people are just as functional as their fully color-perceiving peers. The most common forms of the condition are more nuisance than they are dangerous. Still, even mild forms of color blindness can have consistent impacts on day-to-day life.
Color blind children may run into some difficulties at school. Color is commonly used by educators to organize and present material and if a child is unable to use these cues, some tasks can become a struggle.
Certain jobs are also more difficult for color blind people. While color blindness shouldn’t be seen as limiting an artistic career – several famous painters are known to have the condition – it can complicate work as a designer or in any other field that requires close attention to color.
Color Vision Testing
The most commonly used diagnostic test for color blindness at the moment is called an Ishihara color test. You’ve likely seen one; they’re a collection of colored spots, with a figure or number in the center laid out in different tones. For people with full color vision, it’s easy to spot the figure, but for color blind folks, it may be difficult to see due to muted brightness perception, or completely impossible to see as it simply blends into a background.
While the Ishihara is effective, and widespread, it does have a few problems. First, and most importantly, it requires a trained physician to conduct and interpret a test. Other existing tests, such as the Farsnworth Lantern (FALANT) used by the US Navy, have further problems. The FALANT test is designed to allow sailors to remain in service if they have certain mild forms of color blindness, but becomes less accurate as a result. In high-pressure situations, in which a test can determine eligibility for employment (as in the Navy), cheating and recording information is also an issue.
Computer tests are designed to address all of those weak points by being quicker, more accurate, and much easier to operate and save data from. Not only that, but online tests remove the need for applicants to physically travel to take the test in person, making them extremely useful for anyone hoping to screen a large number of people.
Most current formats are similar to established tests such as the Ishihara. Tests such as the Waggoner Computerized Color Vision Test show a rapid succession of plates to screen for several different types of color blindness. In doing so, they can theoretically not only determine if a test-taker is color blind, but also find further details, such as type and degree of the disorder.
While they’ve hardly replaced physical tests, computerized tests have shown a great deal of promise, even in their early stages. As of now, at least some are known to be equal to traditional screening in terms of accuracy and superior in terms of cost and time taken to complete.