Colour blindness affects approximately 8 percent of men and 0.5 percent of women, making it considerably more common than most people assume. The majority of people with colour vision deficiency go through childhood and often into adulthood without a formal diagnosis, not because the condition is hard to detect, but because it is rarely tested unless someone specifically requests it.
This guide explains what colour blindness actually is, who should be tested, and yes, it can be detected during a routine eye exam at an Edmonton optometry clinic.
What Is Colour Blindness?
Colour blindness is more accurately called colour vision deficiency. It is a reduced ability to distinguish between certain colours, not an absence of colour perception in most cases. The most common form is red-green colour deficiency, where distinguishing between shades of red, green, and related colours is difficult or impossible. Blue-yellow colour deficiency is less common. Complete colour blindness, where everything is seen in shades of grey, is very rare.
Colour vision deficiency is most often congenital and inherited. It does not typically change over a lifetime. Acquired colour vision changes, however, can develop as a result of certain eye diseases, medications, or neurological conditions. This is why colour vision testing is clinically relevant even for adults who have previously been told their colour vision is normal.
How Is Colour Blindness Detected?
Colour vision screening during a comprehensive eye exam in Edmonton typically uses the Ishihara test, which is the most widely used and recognized tool. It consists of a series of plates covered in coloured dot patterns. A number or shape is visible to people with normal colour vision but not to those with specific colour deficiencies. The Ishihara test is quick, reliable for screening purposes, and gives an immediate indication of whether a colour deficiency is present and its approximate type.
More detailed colour vision assessment using tools like the Farnsworth-Munsell 100 Hue test or the D-15 panel test can quantify the degree and specific type of deficiency more precisely. This level of assessment is relevant for vocational purposes, educational assessment, or clinical situations where the nature of the deficiency needs to be fully characterized.
Who Should Be Tested for Colour Blindness in Edmonton?
Children before school age benefit from colour vision screening because colour coding is used extensively in early education. A child who cannot distinguish certain colours may struggle with activities without understanding why, and without a diagnosis, teachers and parents are unlikely to provide appropriate accommodations. Our pediatric eye exams in Edmonton include colour vision screening as a standard component.
Children with unexplained learning difficulties are worth screening specifically for colour vision deficiency. Not because colour blindness causes learning problems directly, but because a child working with colour coded materials in a classroom without knowing they cannot distinguish the relevant colours is at a real disadvantage that is easy to remove once identified.
Adults entering careers with colour vision standards should have a formal assessment. Pilots, electricians, law enforcement, firefighters, and some medical fields have colour vision requirements. Knowing where you stand before pursuing a specific career path is important, and some roles have accommodations available for certain types of deficiency.
Patients who notice changes in how colours appear to them should discuss this with their optometrist. Acquired changes in colour perception can be a sign of developing eye disease, macular changes, optic neuritis, or medication side effects. Any noticeable shift in colour perception warrants evaluation.
Questions Edmonton Patients Ask About Colour Blindness
Q: My child seems to have trouble with colours. How do I know if it is colour blindness?
The signs can be subtle. A child might consistently use the wrong colour when drawing, have difficulty identifying certain objects by colour, or become frustrated with colour-dependent activities. They may not be able to articulate what is wrong because they have no reference for how others see colour. A colour vision screening during a children’s eye exam in Edmonton takes only a few minutes and gives you a clear answer.
Q: Is colour blindness more common in boys?
Yes, significantly. Red-green colour deficiency is an X-linked condition, meaning it is carried on the X chromosome. Men have only one X chromosome, so if it carries the deficiency gene, they are colour deficient. Women have two X chromosomes and need both to carry the gene to express the deficiency, which is much less common. This is why approximately 8 percent of men are colour blind compared to 0.5 percent of women.
Q: Can colour blindness be corrected or treated?
Congenital colour blindness cannot be cured. Certain specialty tinted lenses, such as EnChroma lenses, can enhance contrast between some colours for patients with specific types of red-green deficiency. They do not produce normal colour vision, but some patients find them helpful in specific situations. The primary value of a diagnosis is understanding the condition, making practical adaptations in daily life and education, and identifying any vocational implications early.
Q: I have been colour blind my whole life and it has never caused me problems. Do I need to be formally tested?
If you are managing well and your daily life and career do not require colour discrimination, a formal assessment is not urgent. However, if you have children, knowing whether you carry the gene is relevant for them. And if you ever notice changes in how you perceive colour compared to your baseline, that change is worth investigating as an acquired colour vision shift can indicate something developing in the eye or optic nerve.
Q: Will colour blindness affect my child’s ability to drive?
Standard colour blindness, specifically red-green deficiency, does not prevent someone from obtaining a driver’s licence in Alberta. Traffic signals are distinguished by position as well as colour, and most colour blind individuals adapt successfully to driving. Specific commercial driving licences and some specialized vehicle operations may have colour vision requirements worth checking individually.
Book a Colour Vision Test in Edmonton
If you have never been tested for colour blindness, have a child you suspect may have a colour vision deficiency, or have noticed any changes in how you perceive colour, a comprehensive eye exam is the straightforward next step. Contact Eyes On Optometry to book your eye exam in Edmonton and ask specifically about colour vision testing at your appointment.