The Colour Vision Illusion: What Opticians, Parents and Patients Need to Know

Colour vision deficiency is far more complex than simply being “colour blind”.In this special episode, recorded around Colour Vision Deficiency Awareness Day, Garry Kousoulou is joined by Mark Hickson, Programme Leader for face-to-face teaching at Bradford College and lecturer in ophthalmic dispensing and visual optics.Mark is a qualified dispensing optician with a specialist interest in visual perception, and this conversation explores what colour vision really is, how the brain interprets colour, why colour vision deficiency occurs, and why the optical profession may need to give the subject far more attention.One of the most fascinating ideas discussed is that colour itself is not a physical property in the way most of us imagine. Light has different wavelengths, but the colours we experience are constructed by the brain. Mark explains how cone cells, rod cells and higher visual processing all contribute to the way we perceive the world around us.The episode also looks closely at colour vision deficiency and the genetics behind it. Mark explains why congenital colour vision deficiency is far more common in men, how the X chromosome is involved and why a child with colour vision deficiency may have absolutely no idea that they see the world differently from everybody else.That creates an important challenge for parents, teachers, opticians and schools.A child may not complain that something is wrong because, to them, their vision has always been normal. Instead, clues may appear through behaviour at school, difficulties with colour-coded learning materials or problems distinguishing certain colours.Garry and Mark also discuss the Ishihara colour vision test, one of the most recognisable tests used in eye care. They look at the different types of Ishihara plates, how the test should be used, why lighting and presentation matter and why old or faded testing books may not give reliable results.This leads to a bigger question for the optical profession: are we testing colour vision often enough?The conversation explores whether dispensing opticians and optical assistants could play a greater role in colour vision screening and whether practices should routinely have access to recognised colour vision tests.The discussion then moves into careers.For some occupations, accurate colour discrimination can be important for safety or professional requirements. The episode considers careers such as train driving, aviation, the military, electrical work and even highly specialised jobs such as producing prosthetic eyes.However, colour vision deficiency should not simply be viewed as a limitation.Mark shares the remarkable historical example of people with colour vision deficiency sometimes being able to detect camouflage more effectively because they are less distracted by certain colour patterns.The episode also touches on one of the most famous examples of visual perception: the blue-and-black or white-and-gold dress illusion. Different people can look at exactly the same image and genuinely perceive different colours, demonstrating just how much colour perception depends on the brain rather than simply the eye.This is a fascinating conversation for dispensing opticians, optometrists, optical assistants, students, parents, teachers and anyone interested in how human vision works.If you work in optometry, ophthalmic dispensing or eye care, this episode may encourage you to think differently about how often colour vision is discussed and tested in practice.And if you are a parent, teacher or someone living with colour vision deficiency, it is a reminder that seeing colour differently does not necessarily mean seeing the world less clearly. It simply means the brain may be interpreting that world in a different way.Featuring:Garry Kousoulou – Dispensing Optician and host of The Optician ShowMark Hickson – Programme Leader and Lecturer in Ophthalmic Dispensing and Visual Optics at Bradford College.