What causes color blindness?
The cause of color vision deficiency (CVD) is not known with certainty. There are several theories about its origin, but none have been proven conclusively. Some scientists believe that it results from a genetic defect in the eye’s photoreceptors or rods and cones. Others think that it results from damage to the retina, which converts light into electrical impulses. Still others think that it results from some environmental factor such as ultraviolet radiation or certain drugs.
How is color blindness inherited?
Color blindness is passed down through the male line only. Fathers will always pass the trait on to their sons, but not to their daughters. This is because the gene for color blindness resides on the X chromosome. Women have two of these and so usually have a back-up, if one is defective. Men only have one and so if they have the defect, they will be unable to differentiate between some colours.
How to check for color blindness?
There is a simple online color blindness test that will give you an indication of whether you suffer from the condition or not. The Ishihara test is a good place to start, but it is not always 100% effective at picking up the more severe forms of the disease. If you suspect that you have some form of CVD, you should ask your GP to refer you to a Ophthalmologist. They are the professional that is able to diagnose the condition and give you the correct treatment.
What type of color blindness do I have?
There are two main types of colour blindness:
Genetic: the most common form of colour blindness is known as red-green colour blindness and is genetic. Around 1 in 12 men in European populations are affected by it and 1 in 200 women.
This is due to the X chromosome carrying the colour blindness gene.
Acquired: the second most common form of colour blindness is known as blue-yellow colour blindness and is acquired. This can be caused by a head injury or illness.
Other types of acquired colour blindness include protanomaly and protanopia, which both affect the red end of the colour spectrum, affecting men more than women. Tritanomaly is an acquired colour vision defect that affects blue-yellow colour blindness, but only slightly.
Do I need treatment?
Not all forms of colour blindness need treatment as you can lead a normal, happy and fulfilling life without being able to differentiate between all colours in the way that others can. However, if the condition is acquired rather than genetic, you should have treatment to help you live a normal life. This can take the form of special glasses that allow you to differentiate between different colours or, in serious cases, a special contact lens. If you have tritanomaly, which only affects the blue-yellow colour spectrum, you may not need any treatment at all.
How do I get glasses or contact lenses?
If the Ophthalmologist decides that you need either glasses or contact lenses, they will fit you with the most appropriate one. They will normally discuss any existing medical conditions you have and how this may or may not impact on your ability to use the glasses. They will then provide you with a new pair of glasses or lenses. They may ask you to return in a week or two to check that the prescription is correct.
How do I choose the right frames?
Once you have been given a correct prescription for your new glasses, you need to choose the right frames for you. It’s important that the frames fit well and suit your face. The Ophthalmologist will help you choose the right frames and, as a guide, the following tips may be useful:
Choose sturdy frames.
Choose a style that suits your age and lifestyle.
Make sure the frames fit well and are comfortable.
Make sure the lenses are clean and scratch-free.
Check the lenses for marks, scratches and cracks before choosing your frames.
Ask for your prescription to be put in non-glare coating.
Glasses will not be covered by health insurance.
What will it cost?
Most insurance policies won’t cover eye tests. Glasses, contact lenses and other tests, such as the colour blind test, are often not covered by medical insurance. In America, a basic eye test will cost between $50 and $100 but an extended eye test, which is the type usually recommended for those with colour blindness, will cost more, around $300. The cost of the glasses or contact lenses themselves is not included in this price and will cost more. They can be very expensive.
What other tests are there?
If you have been referred for further testing, it is important that you see the consultant in order to discover exactly what the problem is. However, other tests may be taken to discover the underlying cause of the colour blindness. These can include:
Thyroid tests – these measure the levels of thyroid hormones in your blood. If these are abnormal, they can cause colour blindness as well as a range of other symptoms.
Urine tests – the urine can show abnormalities that cause colour blindness. A 24-hour urine test can reveal a range of metabolic conditions, from hypercalcaemia through to kidney problems.
Blood tests – these can reveal a wide range of underlying causes for colour blindness. They can also rule out other medical problems.
There are a wide range of underlying medical conditions that can cause colour blindness. Many of these can be treated and it’s important to see an expert who can assess the underlying cause and recommend the best course of treatment.
Treatments for colour blindness
There is no cure for red-green colour blindness. There is also no treatment – ignoring the problem and simply dealing with it is the only option.
For example, some people with the most common type of colour blindness, red-green colour blindness, can join the police force or army as they only need to be able to tell the difference between red and green traffic lights.
There are, however, some underlying causes of colour blindness that can be treated. If you have been diagnosed with any of the conditions mentioned above, you should seek medical advice about treatment options.
This can include the following:
Vitamins and minerals – certain vitamins and minerals are essential for the normal functioning of the eyes. In some cases, a lack of these vitamins can cause colour blindness.
A course of supplements can, in these cases, improve colour vision.
Drugs – some drugs are available that can cure colour blindness in diseases such as Toxoplasmosis and others. These are not usually available on the NHS.
Laser surgery – in some cases, retinal problems can be corrected with laser surgery and colour blindness eliminated. Again, this is not usually available on the NHS.
Some information taken from NHS direct
Useful products for colour blindness
As with many conditions, there are numerous products available that can help colour blind people. They can be purchased from most major high street retailers, such as Boots and Superdrug, or online.
Here are just a few:
Sources & references used in this article:
- Facts of color-blindness (DB Judd – JOSA, 1943 – osapublishing.org)
- Effect of Therapist Color-Blindness on Empathy and Attributions in Cross-Cultural Counseling. (AW Burkard, S Knox – Journal of counseling psychology, 2004 – psycnet.apa.org)
- The myth of colorblindness (DA Strauss – The Supreme Court Review, 1986 – journals.uchicago.edu)
- Opsin genes, cone photopigments, color vision, and color blindness (LT Sharpe, A Stockman, H Jägle… – Color vision: From …, 1999 – books.google.com)
- Functional photoreceptor loss revealed with adaptive optics: an alternate cause of color blindness (J Carroll, M Neitz, H Hofer, J Neitz… – Proceedings of the …, 2004 – National Acad Sciences)
- What group?” Studying whites and whiteness in the era of “color‐blindness (AE Lewis – Sociological theory, 2004 – Wiley Online Library)
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- The impact of multiculturalism versus color-blindness on racial bias (JA Richeson, RJ Nussbaum – Journal of Experimental Social Psychology, 2004 – Elsevier)
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