Color Vision Deficiency

Color vision deficiency refers to the inability to properly distinguish between certain color shades. Color blindness is often used to describe this particular condition of vision, though few people are actually fully color blind.

The majority of individuals with this deficiency are able to see colors, but they find it difficult to proper differentiate between these colors:

  • Yellows and blues (less common)
  • Certain shades of greens and reds (more common)

Individuals who are completely color blind, which is referred to as achromatopsia, are only able to see things in shades of gray or white and black.

Color vision deficiency can range anywhere from to severe, depending on the deficiency’s cause. If it is inherited, it can impact both eyes, but if it is a result of an illness or injury, it typically only affects one eye.

Color vision can be possible as a result of photoreceptors in the eye’s retina known as cones. Cones consist of light-sensitive pigments that allow us to recognize colors. Each cone is found in the central section of the retina, also known as the macula, and is sensitive to either blue, green, or red light (short, medium, or long wavelengths). These cones recognize the lights based on their respective wavelengths. 

Generally, the pigments located within the cones register varying colors and send that data through your optic nerve to your brain, enabling you to decipher countless color shades. However, if the cones do not have at least one light-sensitive pigment, you won’t be able to see the different colors.

The most common type of color vision deficiency is red-green. Now, this doesn’t mean that individuals with this particular form of deficiency are unable to see these two colors at all. Instead, they just have a more difficult time distinguishing between them, which can depend on the lightness or darkness of the colors.

Another type of color vision deficiency is blue-yellow. This form of deficiency is much rarer and a more severe type of loss of vision color than red-green due to the fact that individuals with this type of deficiency tend to have red-green color blindness as well.

In both of these instances, individuals with color vision deficiency tend to see gray or neutral areas where a certain color should appear.

What Is the Cause of Color Vision Deficiency?

As a general rule, color vision deficiency is a condition that is inherited and caused by a common X-associated recessive gene, which is a gene that is passed to a son from his mother. However, injury or disease that can cause damage to the retina or optic nerve can also result in color recognition loss. Some of the diseases that may result in color deficits are as follows:

  • Diabetes
  • Parkinson’s disease
  • Alzheimer’s disease
  • Macular degeneration
  • Glaucoma
  • Multiple sclerosis
  • Sickle cell anemia
  • Leukemia
  • Chronic alcoholism

Some additional causes for deficiency of color vision are as follows:

  • Medications – Drugs that are used to treat infections, high blood pressure, heart problems, psychological problems, and nervous disorders can impact your color vision.
  • Aging – The ability to properly see colors can gradually lessen as you get older.
  • Chemical Exposure – When you come in contact with specific chemicals like styrene and fertilizers, it may result in color vision loss.

In many cases, color deficiency can be caused by genetics. Roughly eight percent of Caucasian males are born with at least some amount of color vision deficiency. Women are generally the carriers of the color vision deficient gene; however, roughly .05 percent of women have the deficiency. The severity of the inherited deficiency typically remains constant over the course of an individual’s life, and it doesn’t result in additional loss of vision or blindness.

How Can Color Vision Deficiency Be Diagnosed?

An eye examination is used to diagnose color deficiency. The individual is shown a series of pictures that are specially designed and are composed of colored dots that are known as pseudoisochromatic plates. The individual is asked to look for numbers within the colored dots. Individuals who have normal color vision will be able to see a number, whereas individuals who have a color vision deficiency will not be able to see the number. On some pictures, an individual who has normal color vision will be able to see one number, whereas an individual with a color vision deficiency will see a different number.

Pseudoisochromatic plate testing can help an eye doctor determine if a deficiency exists and the type of the color vision deficiency. However, it may be possible for additional testing to be needed to determine the nature and degree of deficiency. 

An individual may have inadequate color vision and not even be aware of it. Often, people who have red-green color vision deficiency are not aware of their issue due to the fact that they have learned to see the appropriate color. For instance, the leaves on trees are green, so individuals call the color that they see green. 

In addition, parents may not necessarily suspect that their children have the deficiency condition until a situation arises that causes misunderstanding or confusion. Early detection of the condition is crucial since many learning materials rely very heavily on the use of color coding and/or color perception. For that reason, the American Optometric Association recommends children undergo a comprehensive exam prior to beginning school.

How Can Color Vision Deficiency Be Treated?

Currently, there is not a cure for inherited color deficiency. However, if the cause is an eye injury or illness, treating the conditions could cause your color vision to improve. 

Utilizing specially tinted eyeglasses or wearing a contact lens with a red tint on one eye may increase your ability to distinguish between colors, although there is nothing that will be able to truly make them see the deficient color. 

The majority of individuals with a deficiency can find ways to work around their problem of not being able to see certain colors by:

  • Organizing and labeling furniture, clothing, and other colored objects with the helps of family or friends, which will help with the ease of recognition.
  • Remember the order of things rather than the color of things. For instance, a traffic light is red, yellow, and green from top to bottom.

Color vision deficiency may be frustrating, and it may reduce participation in some jobs. However, in most cases, color vision deficiency isn’t a serious threat to your overall vision. With time, practice, and patience, individuals are able to adapt. In the early stages, there have been gene therapies that have successfully restored color vision in animals, which are being developed for humans. 

If you would like to learn more, contact us at Performance Vision, Inc.