| Oliver Sacks, in the Case of the Colorblind Painter, | | | | tests. The changes can be very subtle which is why |
| describes how an artist, who was famous for his | | | | early reporting is essential.If you acquire color |
| brilliantly-colored abstract canvasses, suddenly and | | | | deficiencies you are more likely to encounter difficulties |
| irreversibly loses all color perception as the result of a | | | | in correctly naming colors. This is because life-long |
| car accident. This tragic case depicted by Sacks is | | | | experience with defective color perception enables |
| one example of an acquired color vision | | | | those with the inherited form to use compensatory |
| deficiency.What were once vibrant works of art now | | | | techniques to overcome their handicap.Because |
| appeared to him grayish or black and white. It was a | | | | acquired color vision deficiencies are the result of life |
| devastating blow for a lifelong painter whose art and | | | | events, they can arise from a variety of different |
| life were now without meaning. | | | | causes affecting the retina, visual pathways or areas |
| Not all cases of this affliction, however, are as sudden, | | | | of the brain which process color information.A wide |
| complete or permanent: onset can be slow and | | | | range of prescription drugs, conditions such as multiple |
| appreciation of colors can change gradually over time | | | | sclerosis, diabetes and cardiovascular diseases, some |
| depending on the particular eye disease.However, | | | | liver diseases and many eye diseases can affect the |
| whereas inherited alterations to color vision tend to | | | | cone nerve cells which enable us to discriminate fine |
| remain stable through life, late onset color vision | | | | detail and colors by day.As a result, and often in only |
| changes can be an early sign of disease or a side | | | | one eye at a time, color vision is temporarily or |
| effect of prescribed medication. It is important, | | | | permanently changed. Both men and women are |
| therefore, that you consult your doctor should you | | | | affected equally.Sufferers from arthritis, heart disease |
| become aware of any changes in your perception of | | | | and depression sometimes find their color vision |
| color.To clarify matters, let's look at the differences | | | | impaired as a side effect of their long-term use of |
| between acquired color vision deficiency and inherited | | | | prescription drugs. Even stroke patients who take |
| or congenital deficiencies:Typically congenital | | | | aspirin over many years to thin the blood can |
| deficiencies involve confusion over red and green. | | | | encounter altered color perception.Cataracts, glaucoma |
| Acquired deficiencies more often than not are a | | | | and the majority of eye problems affecting the retina |
| blue-yellow problem.There is a gender imbalance in | | | | or nerve pathways to the brain are associated with a |
| congenital defects as they are linked to the X female | | | | reduced ability to differentiate colors, including blues and |
| chromosome. This means mothers (whose vision will | | | | greens.But the most widespread form of acquired |
| be apparently normal) carry the defect to their sons. | | | | color vision deficiency in the developed world, affecting |
| Inherited color vision deficiency is, therefore, more | | | | some 23 per cent of people over the age of 65, is |
| prevalent in males than females.By contrast, acquired | | | | age-related macular degeneration (AMD). Involving a |
| defects are not gender-related except by gender | | | | loss of the cone-rich area of central vision (the macula) |
| differences in the experience of brain trauma injuries, | | | | where color vision is sharpest it often leads to |
| for example.As touched on above acquired defects | | | | blindness.Finally, the condition known as optic neuritis, |
| are less likely to be stable over time. With congenital | | | | which can result in a distortion or lack of color vision, |
| defects both eyes tend to be affected equally | | | | illustrates well how one example of acquired color |
| whereas acquired color deficiencies are more likely to | | | | vision deficiency can be an indicator of two very |
| affect one eye more than the other. Stroke victims | | | | different prognoses.This inflammation of the optic |
| typically experience a more pronounced color | | | | nerve is sometimes diagnosed in young children |
| deficiency in one eye.Acquired defects are not as | | | | following an illness such as measles or mumps. |
| easily diagnosed or detected with standard color vision | | | | |