Did you know that color blindness is not a form of blindness at all, but a deficiency in the way we see color? Color blindness tends to be hereditary caused by abnormal photopigments. This deficiency occurs when a patient can not distinguish between certain colors, such as red and pink. The colors manage to look the exact same to their eyes.

There are two types of cells inside your retina that detects light. The medical terms are rods and cones. The cone cells are in the center of your vision and can identify colors, while the rods can only sense between light and dark. When the cone cells fail to work, this prevents the patient from seeing the difference in colors which results in having a color deficiency. The three types of cones that can be seen include: red, blue, and green. The brain takes this information from these cone cells to define our color observation.



There are numerous types and levels of color blindness. We wanted to share the most common color deficiencies.


Protanomaly is considered a type of red-green color deficiency. The cones are not able to reveal enough red and can be sensitive to other colors such as greens, yellows, and oranges. For example, the greens, yellows, and oranges will appear similar making it hard to tell the difference in low light.


Deuteranomaly works similarly to Protanomaly. The variance is that the cones can not detect enough green. Having this color deficiency, patients struggle to differentiate between hues.


Tritanomaly is very rare among patients compared to Protanomaly and Deuteranomaly. Tritanomaly happens when the Tritan photopigments are absent or have limited function. This can cause blue to appear greener.

Complete color blindness

Some patients suffer from complete color blindness. There are two types: Cone Monochromacy and Rod Monochromacy. Both of these are considered to be rare. The Cone Monochromacy occurs when two of the cone cell photopigments do not work. When this deficiency happens, the brain has difficulty comparing colors to one another due to the lack of signals sent from the cones. The Rod Monochromacy is the most severe form of color blindness and tends to be noticeable at birth. This condition transpires when none of the cone cells have working photopigments and only allow patients to see black, white, or grey.



Your Optometrists can utilize several tests to diagnose for color deficiencies in your vision. The most common test is the Ishihara Color Test. This assessment is used for red-green color blindness. The Ishihara Color Test includes a series of color plates that contains a collection of dots varying in color and size. The numbers on the plate will be difficult to identify for patients with Protanomaly or Deuteranomaly. The Farnsworth-Munsell Hue Test uses a set of blocks that have similar colors, but different shades in order to measure the ability to color differentiate. For example, the exam will have you arrange 10 blocks of one color such as blue from light to dark. If you have an artistic job such as graphic design or photography, your employer may test your color perception with the Farnsworth-Munsell Hue Test.



Currently, there is no treatment for color blindness. Patients with a red or green color deficiency can get special lenses prescribed by their Optometrist to help with their vision needs and daily life activities.

Schedule your annual eye exam at one of our One Hour Optical locations to detect any vision conditions.

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