Some Patients Can Only View a Range of Color

Our eyes possess four unique cones: one for detecting light and the other three, known as Photopigments, allow us to perceive color through its wavelengths.

All substances absorb different wavelengths of light, but the color that remains when none are absorbed will determine its hue. In other words, whatever is not taken in by an object or material – whether it’s a short or long wavelength – dictates what color appears to our eyes. Human vision can be affected if photopigments in the eyes are damaged or missing, resulting in color blindness.

Although these individuals might still perceive colors, they are unable to see certain wavelengths. The most commonplace form of color blindness is red-green, which can be broken down into protanopia (blindness to red) and deuteranopia (blindness to green). An absence of long- and medium-wavelength cones produces this irregularity. Much less common is tritanopia, or blue-yellow color blindness, which can be caused by the absence of short-wavelength cones in individuals with certain medical conditions.

Testing

To determine if someone has color blindness, eye care professionals often use the Ishihara color test. This test involves a series of plates with colored dots arranged in patterns. If the patient cannot distinguish the number or shape that is hidden within the dots color blindness is likely. For those who cannot see the hidden figure, it may indicate color blindness.

Another test that may be done is the Farnsworth test. This test measures the ability to order hues in a color spectrum. It is important to note, these tests are not foolproof and may not detect more subtle forms of color blindness.

Inherited or Developed

Color blindness is inherited from the X chromosome and is most common in men. Mothers, who are typically carriers of the color blindness gene, have a fifty percent chance of passing it on to their sons. However, if their partner is also color blind then their daughter has a one-hundred percent likelihood of being a carrier and a fifty percent probability of becoming afflicted.

Developing color blindness can occur as a result of damage to the optic nerve or retina. Other causes are exposure to certain medications or chemicals or as a symptom of other underlying health conditions. Diabetes and multiple sclerosis are two of the more commonly known diseases associated with color blindness. These conditions can lead to a temporary/reversible symptom or permanent color blindness. Individuals with acquired color blindness need to discuss their diagnosis with their healthcare provider to explore potential causes and treatment options.