Colour blindness and contact lenses for colour perception

Medically reviewed by Sharon Copeland on 11 March 2021

A team of researchers at the University of Birmingham have developed a new contact lens to help with colour blindness and enhance colour perception. These contact lenses use a low-cost dye to help distinguish red from green colours and vice versa.

Colour vision deficiency

The formal term for colour blindness is 'colour vision deficiency'. The condition is hereditary and more common in men than women. Colour blindness is said to affect 1 in 12 men and 1 in 200 women. Those affected by the condition struggle with identifying specific colours and differentiate between them.

Colour blind people usually have difficulty distinguishing shades of red, yellow, green, brown and orange.

Causes of colour blindness

In the vast majority of cases, colour vision deficiency is caused by a genetic fault passed on to a child by their parents. It occurs because some of the colour-sensitive cells in the eyes, called cones, are either missing or do not work properly.

Occasionally, colour vision deficiency may develop later in life as the result of:

• an underlying health condition, such as diabetes, glaucoma, age-related macular degeneration and multiple sclerosis

• a side effect of a medication, including digoxin, ethambutol, chloroquine, hydroxychloroqine, phenytoin and sildenafil

• exposure to harmful chemicals, such as carbon disulphide and styrene

Many people also find it more difficult to distinguish between colours as they get older. This is normally just a natural part of the ageing process.

Types of colour blindness

The most common type of colour blindness is a red-green deficiency, however other types of colour blindness include:

• Protonomaly-this causes reduced sensitivity to red light and causes those affected to get confused by shades of the same colour from the red-green-yellow spectrum.

• Protanopia-those with protanopia will see red as darker than usual and are likely to confuse reds, yellows and greens.

• Deutranomaly-causes those affected to have a reduced sensitivity to green light and confuse shades of the same colour from the red-green-yellow spectrum.
• Deuteranopia-this causes confusion between reds, yellows and greens with the hues tending to shift towards the red end of the colour spectrum.

Diagnosis of colour blindness

Colour blindness can be diagnosed using colour vision tests such as the Ishihara test and the colour arrangement test. Your optometrist should test your colour vision as a matter of routine, but not all chains of opticians in the UK do this test routinely you may have to request a colour vision test specifically and sometimes even pay for this as an addition to your test.

The Ishihara test will require the participant to read the numbers on an image made up of coloured dots.

The colour arrangement test comes in various forms which involve matching or arranging coloured objects according to their shades.

Can color vision be corrected?

Researchers at the University of Birmingham have developed an inexpensive dye which can be applied to contact lenses to correct color vision.

The dye works by blocking the band that lies between red and green wavelengths so that red and green colours can be better differentiated.

People with a red-green deficiency were asked to test dyed lenses. The test required them to look at numbers and their surroundings and to say whether the lenses improved the colours they saw or the clarity of the numbers.

The results proved that dyed lenses improve colour perception for those who are colourblind.

Is there a cure coming soon for color blindness?

While colour blindness can be corrected with dyed contact lenses; it is not possible to cure the condition.

How can red green colourblindness be improved?

Certain forms of red-green colour blindness can be improved with unique color corrective glasses or contact lenses. While these glasses don't restore normal colour vision, they can help people distinguish red and green hues more readily, making them appear more vibrant. However, it's important to note that these glasses don't work for everyone.

What is the current status of research on color blindness?

Research is currently being conducted on new ways to treat colour blindness and includes research focusing on gene therapies.

Potential gene replacement therapy for red-green colour blindness has been tested on animals.

According to WebMD, scientists have demonstrated that by 'placing certain color-recognizing (photopigment) genes into the cells of male monkeys known to be red-green color-blind allows the animals to tell the difference between the two colors.' They then had the monkey's take a computer-based color vision test to test their vision.

This study suggested that the brain might have the ability to reprogram itself when given new sensory information such as colour recognizing receptors.

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