Colour Blindness 101

The information you need to know about colour blindness..

I recently spoke at a mom’n’tot group and one of the moms had some questions regarding colour blindness.  Her questions was “Do people with colour blindness see in black and white?”  The answer is NO.  Someone who is colour blind usually has trouble distinguishing red/green or blue/yellow colours.  Although some cases of colour blindness can be acquired later in life, the most common type is genetic and present at birth.  It is a sex-linked genetic disorder, and is a result of a mutation in the X chromosome.  Since males have one X and one Y chromosome, they are more commonly affected (8{4422c3e9d6d956ffe17c4a9703f8867adf328a271a08c00de098d82d34d0cfb5} male vs 0.5{4422c3e9d6d956ffe17c4a9703f8867adf328a271a08c00de098d82d34d0cfb5} female).   The X chromosome is always from the mother, so if she is a carrier for the gene, she usually passes it onto her son.  Cone cells in the retina are responsible for our perception of colour.  The mutation occurs to one or multiple types of cone cells in the retina, therefore colour blindness occurs in varying degrees..  There are three types of inherited or congenital color vision deficiencies: monochromacy, dichromacy, and anomalous trichromacy.  Although there is no cure for this type of colour blindness, tinted glasses or contact lenses have been shown to help these patients distinguish colours better by differentiating luminosity (brightness).

At Avenue Eyecare, children who are old enough to recognize numbers or trace lines are screened for colour blindness with the ishihara colour plates test.  For those who don’t see the numbers on the ishihara colour plates, further testing with the D-15 caps can be done at our clinic.  This is a usual requirement for many pre-employment vision evaluations. Knowing whether your child is colour blind is helpful when it comes to learning.  When teachers are made aware of this, activities can be modified for colour blind students.  Colour blindness can also shape your child’s career path as certain jobs depend on normal colour vision.  Bring your child to get tested if you haven’t already, the sooner you know the better!

Also to mention some famous people with colour blindness: Mr. Rogers, Meat Loaf, Jack Nicklaus and Howie Mandel.

Dr. Jessica Chang ODdrchang@avenueeyecare.com