Colour Blindness

What is colour blindness?

If you experience colour blindness (colour vision deficiency), it indicates that your perception of colours differs from that of the majority. Typically, colour vision deficiency makes it challenging to distinguish between specific colours.

In most cases, colour vision deficiency is hereditary. While there is no known cure, specialized glasses and contact lenses can assist individuals in perceiving differences among colours. Generally, those with colour vision deficiency do not encounter significant issues with daily activities.

What are the types of colour vision deficiency?

The most prevalent form of colour vision deficiency makes it difficult to differentiate between red and green hues. Another variant causes blue and yellow to appear indistinguishable. In rare instances, individuals may experience complete colour vision deficiency, meaning they perceive no colour whatsoever.

What are the symptoms of colour vision deficiency?

The primary indicator of colour vision deficiency is the inability to perceive colours as most individuals do. If you have colour vision deficiency, you might struggle with:

  • Distinguishing between various colours

  • Assessing the brightness of colours

  • Recognizing different shades of colours

Symptoms of colour vision deficiency can often be so subtle that they go unnoticed. This is why many individuals with colour vision deficiency remain unaware of their condition. Typically, people adapt to the variations in their colour perception.

Those with severe cases of colour vision deficiency may experience additional symptoms, such as rapid side-to-side eye movements (nystagmus) or heightened sensitivity to light.

Am I at risk for colour vision deficiency?

Men are significantly more likely than women to develop colour vision deficiency. You may also have an increased risk if you:

  • Have a family history of colour vision deficiency

  • Suffer from specific eye conditions

  • Have certain health issues, such as diabetes, Alzheimer’s disease, or multiple sclerosis (MS)

  • Are taking particular medications

  • Are of Caucasian descent

If you suspect you might have colour vision deficiency, consult your eye care professional about undergoing an evaluation.

When should my child’s eyes be examined?

Diagnosing colour vision deficiency in children can be challenging. Kids with colour vision deficiency may attempt to conceal their condition. However, having colour vision deficiency can hinder their ability to read from a chalkboard or engage in other activities, so it’s advisable to have your child’s eyes examined if you have concerns.

Schedule an eye exam for your child if there is a family history of colour vision deficiency or if they appear to struggle with learning colours.

Request that your child’s eye doctor conduct a test. Additionally, it may be possible to have your child’s eyes examined at their school.

What causes colour vision deficiency?

Most individuals with colour vision deficiency are born with the condition. This is primarily because the most common forms of colour vision deficiency are genetic, meaning they are inherited from parents.

Colour vision deficiency can also arise from damage to the retina (the light-sensitive tissue layer at the back of the eye), the optic nerve (which connects the eye to the brain), or the brain itself. Examples of injuries that may lead to colour vision deficiency include:

  • Retinal detachment (when the retina is separated from its normal position at the back of the eye)

  • Eye injuries caused by lasers

  • Certain types of brain tumors — particularly those affecting the optic nerve or exerting pressure on the brain

  • Radiation therapy

Colour vision may also deteriorate with age, often due to cataracts (cloudy areas in the eye's lens).

Did you know?

  • Everyone perceives color slightly differently — including those without colour vision deficiency.

  • Approximately 1 in 12 men experience colour vision deficiency.

  • While most individuals with colour vision deficiency are born with it, sometimes the condition may not manifest until later in life.

How can I determine if I have colour deficiency?

Your eye doctor can typically perform a straightforward test to determine if you have colour vision deficiency.

During the most common type of assessment, your eye doctor will present you with a circle composed of various coloured dots. Within this circle, there is a shape made of dots — such as a number, letter, or squiggly line. This shape is easily visible to those without colour vision deficiency, but individuals with the condition may find it challenging to see.

What treatments are available for colour vision deficiency?

There is no cure for inherited colour vision deficiency, but most individuals learn to adapt to it. Children with colour vision deficiency may require assistance with certain classroom tasks, while adults may need accommodations for jobs that depend on colour differentiation, such as graphic design.

If your colour vision deficiency is a result of another health issue, your doctor will address the underlying condition. If you are taking medication that contributes to colour vision deficiency, your doctor may modify your dosage or recommend an alternative medication.

If colour vision deficiency is interfering with your daily activities, consult your eye doctor about potential solutions, such as:

  • Glasses and contacts. Specialized contact lenses and glasses can help individuals with colour vision deficiency distinguish between colours. They function by enhancing the contrast between colours, making them easier to differentiate.

  • Visual aids. Applications allow users to take photos with a smartphone or tablet and then tap on a specific part of the image to identify its colour.