Colour vision deficiency, commonly referred to as colour blindness, is often a misunderstood condition. This is partially because there are several different causes of colour blindness, as well as a variety of ways the condition develops. Is it true that only males are at risk? Are people born with colour blindness? Read on to find out what is fact and what is fiction:
According to HealthLink BC (www.healthlinkbc.ca), people generally have three types of cone cells in the eye. Each type senses red, green, or blue light. Colour blindness happens when you don't have one of these types of cone cells or they don't work correctly. Symptoms include not only an inability to identify colours, but also trouble seeing the difference between shades and brightness.
Red-green deficiency is the most common type of colour blindness, followed by blue-yellow. People with blue-yellow colour blindness usual
ly have problems identifying reds and greens, too. HealthLink BC also notes that some people with severe colour blindness cannot distinguish any colour and see everything in shades of grey, black and white.
The Mayo Clinic lists multiple causes of colour blindness:
- Genetics: Approximately one in 12 males of Northern European descent is born with some degree of red-green colour deficiency. Most females possess genes that counteract the deficiency, so less than one percent of females of Northern European descent have this type of colour deficiency. In other populations, the prevalence of red-green colour deficiency is lower. Blue-yellow colour deficiency is inherited by fewer than one in 10,000 people worldwide. Individuals can inherit a mild, moderate or severe degree of the disorder, and the severity doesn't change over a person’s lifetime if the cause is inherited.
- Diseases: Diabetes, Alzheimer's disease, Parkinson's disease, leukemia and sickle cell anemia can all contribute to colour vision deficiency. Other eye diseases, such as glaucoma and macular degeneration, can impact the ability to see colour as well.
- Medications: Certain drugs that are used to treat conditions like high blood pressure and psychological disorders can cause colour blindness.
- Chemicals: Exposure to chemicals like carbon disulfide and fertilizers can cause loss of colour vision.
- Aging: The ability to see colours can deteriorate slowly as a part of aging.
Although there is no direct treatment for colour blindness, specially designed glasses and contact lenses can often help. Many people, especially those with mild colour blindness, are able to adjust without much difficulty.
Whether or not you think you may be having problems with colour, it’s always good to have regular eye exams with an optometrist or ophthalmologist. They can test colour vision quickly and easily, as well as ask questions about your family history, current medical conditions and medications to help identify any possible issues.
For more information about colour blindness, visit HealthLink BC at www.healthlinkbc.ca/kb/content/mini/hw143997.html#hw143999 and the Mayo Clinic at www.mayoclinic.com/print/poor-color-vision/DS00233/DSECTION=all&METHOD=print.
