Colour Vision Test – Overview, Procedure, Results


A colour test measures the ability to identify the difference among the colours. If you do not pass this test, your doctor may declare you as colour blind. However, the most severe condition of colour blindness is when you’re only able to see the shades of grey.

What causes poor colour vision?

The inability to differentiate the shades of green and red is the most common type of poor colour vision. Such type of condition can be caused due to various factors, such as:

  • Genetics
  • Aging
  • Medications and certain diseases
  • Exposing the eye to chemicals

As per NHS – UK studies around 1 in 12 men and 1 in 200 women experience colour blindness Sometimes a disease that affects your optic nerve can also cause this condition, for example, glaucoma. Some of the most common diseases that causes  colour vision problems are:

It is advisable to get a colour vision test done immediately, in case you feel you’re unable to differentiate the colours. When your child receives a standard eye exam, it’s a good idea to test their color vision as well as visual acuity. Testing for both of these factors will help catch potential issues early in life.

How is a colour vision test done?

An ophthalmologist or eye doctor will perform the test. You will usually be seated in a lit room. The doctor will ask you to close one eye with your palm and look at a series of test cards with your naked eye. Each card has a multicolored dot pattern. Each color pattern contains a number or symbol. If you can identify numbers or symbols, tell your doctor. You should be able to easily distinguish numbers, shapes, and symbols from surrounding dots if you have a normal colour vision.

When you face a color vision impairment, you may not be able to see symbols. Or it may be difficult to distinguish patterns between dots. After checking one eye, close the other eye and look at the test card again. Your doctor may ask you to describe the intensity of certain colors that one eye perceives compared to the other. Normal color vision test results can be obtained, but there might be a loss of color intensity in one or the other eye.

How to prepare for a colour vision test?

If you wear glasses or contact lenses, you should continue to wear them during the test. Your doctor will ask if you have taken any medications or supplements, if you have any medical conditions, or if you’re having any family history of poor color vision. This test is risk-free and requires no special preparation.

What do the test results mean?

The severity of having poor colour vision problems can be varied. This may include:

ProtanopiaDifficulty in distinguishing blue from green and red from green
TritanopiaDifficulty in distinguishing yellow from green and blue from green
DeuteranopiaDifficulty in distinguishing red from purple and green from purple
AchromatopsiaA rare condition of complete colour blindness. In this case, only shades of grey are visible.

You must understand that there are no proven treatment for the above-mentioned problems, however, you can wear specially tinted glasses or red contact lenses in one eye which may improve the ability of some people to distinguish colors, but it doesn’t actually allow them to see the deficient colors. In some cases, the illness that has caused colour vision impairments such as diabetes or glaucoma should be treated immediately in order to improve colour vision.

Summing Up

Colour vision impairment is not a severe condition and it shouldn’t affect the quality of life. However, you may not know to denote a ripe banana or a sunburn in your day-to-day basis. These situations can cause unpleasant effects. If you have a child, it is always good to diagnose colour vision impairments early in life.

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