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Color Blindness

Color blindness, or color vision deficiency, is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions. There is no actual blindness.

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(Source: Wikipedia)

About Color Blindness

Most of us share a common color vision sensory experience. Some people, however, have a color vision deficiency, which means their perception of colors is different from what most of us see. The most severe forms of these deficiencies are referred to as color blindness. People with color blindness aren't aware of differences among colors that are obvious to the rest of us. People who don't have the more severe types of color blindness may not even be aware of their condition unless they're tested in a clinic or laboratory.

Inherited color blindness is caused by abnormal photopigments. These color-detecting molecules are located in cone-shaped cells within the retina, called cone cells. In humans, several genes are needed for the body to make photopigments, and defects in these genes can lead to color blindness.

There are three main kinds of color blindness, based on photopigment defects in the three different kinds of cones that respond to blue, green, and red light. Red-green color blindness is the most common, followed by blue-green color blindness. A complete absence of color vision—total color blindness—is rare.

Sometimes color blindness can be caused by physical or chemical damage to the eye, the optic nerve, or parts of the brain that process color information. Color vision can also decline with age, most often because of cataract—a clouding and yellowing of the eye's lens. NIH - National Eye Institute

What works? Research summarized

Evidence reviews

Boston Keratoprosthesis for the Treatment of Corneal Blindness: Clinical Effectiveness and Cost-Effectiveness [Internet]

This Rapid Response report aims to review the clinical and cost-effectiveness of Boston Type 1 (KPro) keratoprosthesis for the treatment of corneal blindness.

Colour vision testing for diabetic retinopathy: a systematic review of diagnostic accuracy and economic evaluation

Diabetic retinopathy (DR) is caused by pathological changes in the blood vessels of the retina, which can lead to blindness.

Colour vision testing for diabetic retinopathy: a systematic review of diagnostic accuracy and economic evaluation

This well-conducted review concluded that there was insufficient evidence to support the use of colour vision testing alone, or in combination with retinal photography, as a method for screening for retinopathy in patients with diabetes. Given the paucity of good quality evidence, the authors' conclusion seems appropriate and reliable.

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Summaries for consumers

Age-related macular degeneration (AMD): Overview

It is normal for vision to gradually get worse with age. Some people also have medical conditions that further affect their vision. Age-related macular degeneration is one of these. It makes objects look blurry and distorted, especially when you look at them directly, and becomes increasingly difficult to do things like read or recognize faces.

Late Effects of Treatment for Childhood Cancer (PDQ®): Patient Version

The treatment of cancer may cause health problems (late effects) for childhood cancer survivors months or years after successful treatment has ended. Get information about the long-term physical, psychological and social effects of treatment for childhood cancer in this expert-reviewed summary.

Childhood Vascular Tumors Treatment (PDQ®): Patient Version

Childhood vascular tumor treatment depends on the specific type and location, can involve surgery, and may be followed by chemotherapy or radiation. Targeted therapy, immunotherapy, and other medications may be used. Learn more about vascular tumors in this expert-reviewed summary.

More about Color Blindness

Photo of an adult

Also called: Colour blindness, Color vision deficiency, Color vision defects

Other terms to know:
Cone Cells, Retina

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