About 8% of men and 0.5% of women worldwide have a colour vision deficiency. It is more common in men because the gene responsible for most types of colour vision deficiencies are found on the X chromosome.  

People with normal colour vision (trichromats) have all three types of correctly functioning cone cells in their eyes. Cone cells are photoreceptors inside the eyes which respond differently to different wavelengths of light. Cones function best in bright light. There are S-cones (short wavelength - blue), M-cones (medium wavelength - green) and L-cones (long wavelength - red). 

Red-green colour vision deficiency is the most common, due to reduced sensitivity or lack of either M-cones or L-cones. Blue-yellow deficiency is due to reduced sensitivity or lack of S-cones is less common. Lastly total colour vision blindness with no functioning cones or only one type of cone is the least common. 

For more information > Colour Blindess Classification

Colour Vision Screening

We do screening tests for red-green colour vision deficiencies using Ishihara test plates as part of an initial eye exam.

Congenital Colour Vision Grading

For more detail diagnoses and colour vision classification further testing can be arranged at UNSW School of Optometry Colour Vision Clinic.

Phone: 02 9385 4624

UNSW Colour Vision Clinic is equipped to conduct more tests for congenital deficiencies. With test results they can offer more detailed lifestyle and occupational advice.

Acquired Colour Vision Disorders

Patients with new colour vision problems should seek prompt eye health testing. New-onset deficiencies may be due to eye disease of the maculas, retinas or optic nerves, as well as neuropathology.