Colour blindness, or colour vision deficiency, is a hereditary condition that affects 1 in 12 men and roughly 1 in 200 women worldwide. Although a few diseases may cause late-onset colour blindness in some, the majority of affected individuals are born this way with the gene inherited from the mother’s side. With varying types and levels of deficiency, people can be extremely colour blind, or have a very mild case. Often, the affected person does not even know they are colour blind until someone points it out to them.
The most common form of colour blindness is red-green, meaning those affected have difficultly distinguishing between red and green shades, or the colours will appear dull. Those with red-green colour blindness may see red as black, shades of orange and green as yellow, reds as yellow, greens as beige, and could have trouble telling violet from blue, depending on the sub-type. Blue-Yellow colour blindness is extremely rare, and also a result of a genetic defect.
Colour blindness happens due to the failure of light-sensitive cells in the retina responding to the variations in wavelengths that allow us to see an array of colours. These photoreceptors in the retina are called rods and cones. The loss or impaired function of the red or green cones is what causes the colour confusion. There are different kinds of defects in these cones that determine the type and severity of the colour blindness.
Most types of colour blindness are not severe enough to negatively impact day-to-day life, and those with it are often unaware they are missing anything. There are now several companies that sell glasses designed to help the colour blind see what they have been missing. These lenses rely on special coatings and filters to do the job of the defective rods and cones, cutting off wavelengths to enhance certain colours. Another treatment that has been showing promise is gene therapy. Trials are currently being conducted and the doctors who are running the tests have suggested that they could begin human trials as early as 2017. In the procedure, doctors inject a non-destructive virus into the eye. The virus acts as a shuttle, delivering the genes to the cone cells in the retina.
Think you may have a form of colour vision deficiency? An eye exam can determine if you are affected. Find an FYidoctors location near you to schedule an appointment.