FREQUENTLY ASKED QUESTIONS

• How Do I Learn If I’m Color Blind?

  To learn if you are color blind, you can take the EnChroma Color Blind Test. If you have color blindness, Brenart Eye Clinic can tell you what type of color deficiency you have, and if your color vision deficiency is mild, moderate, or strong.

• What Can Color Blind People See?

  Many assume because of its name that “color blind” means a person can only see in black and white. In actuality, the vast majority of people with color blindness do see color, but they see a much smaller range of shades of color compared to a person with normal color vision. In addition, a person with color blindness may miss out on details or not notice objects that would normally be plainly visible, because the color of the details or object is confusingly similar to the surrounding visual context. A classic example is not noticing a ripe red apple in a tree when it is surrounded by green leaves.

  Humans have three primary types of light receptor cells in the retina that respond broadly to red, green, and blue light. Signals from these receptor cells form the basis of color vision, by transmitting neural signals to the brain about the relative amount of each primary color to the visual cortex. It is estimated that the human visual cortex can perceive about 100 levels of sensitivity for each primary channel: 100 x 100 x 100 = 1 million, which is where we get to 1 million perceived shades of distinct color. However, if a person is color blind, for example having red-green color blindness, then the red and green primary channels have an overlap in their signals causing the channels to contain almost the same information. In the most extreme case, called dichromacy, the red and green channels are completely indistinguishable, such that the total number of colors that can be seen is just 100 x 100  = 10 thousand or just 1% of the normal range. Most people with color blindness have only a partial loss of sensitivity, meaning the information is there, but is harder to notice. Depending on the severity, the number of unique shades of color that can be seen is more often estimated to be around 10% of normal.

   

• What Are the Symptoms of Color Blindness?

  The primary symptom of color blindness is color confusion, which means that the person may mis-identify a color as being something other than what people with “normal color vision” see. Another symptom is that details or objects may be overlooked or not readily seen if they have a color that is confused with other colors in the surrounding visual scene.  Color blindness is not known to be correlated with other eye conditions such as myopia, nor with learning disabilities. If you can’t see any color at all and see only in shades of gray, you may have the rare condition called achromatopsia.

  As a person with color blindness, color confusion can show itself in many everyday tasks, resulting in frustrating outcomes such as a mismatched outfit, questionable paint choices, incorrect color naming and difficulty interpreting color coded information such as charts, graphs and maps, which may cause problems at school or work.

  Another task that can be frustrating is driving a car when color blind since for the color blind person, green light tends to look very pale green or nearly white, and red light may seem closer to orange. Color blind drivers often say they look more for the traffic light’s position or to what other cars are doing on the road, rather than at the colors of lights.

• How Many People are Color Blind?

  There are an estimated 350 million people in the world with red-green color blindness (deutan-type and protan-type vision deficiency), or 4% of the total population. Red-green color blindness is acquired genetically through your parents and is expressed by genes on the X-chromosome. Because of the X-linked recessive biology behind red-green color blindness, the condition affects mainly men: about one in 12 men (8%), but also includes about one in 200 women (.5%). Less precise statistics are known about blue-yellow color deficiency, which is most often caused by progressive or age-related eye conditions. Some estimates place the total number at least as high as those for red-green color blindness, and may be increasing due to the trend toward an aging population demographic worldwide. The more rare forms of color blindness include achromatopsia and progressive eye diseases, such as retinitis pigmentosa. Estimates of these conditions are about 1 in 2000 people, or lower, but are known to be greater in certain subpopulations.

• Will EnChroma Color Blind Glasses Work for Me?

  Color blindness is not a singular condition. It encompasses a range of conditions, from mild to severe, that can cause each person to see color differently. EnChroma glasses are designed to improve color vision of people with forms of anomalous trichromacy, which are estimated to comprise four out of five cases of color blindness. The most common types are Protanomaly and Deuteranomaly, which are forms of partial red-green color blindness. In the most extreme cases, the complete absence of one of the cone photopigments, called Protanopia or Deuteranopia, are considered dichromats who may see limited results due to the complete inability to see red and green color differences. Reduced color discrimination of shades of blue and yellow is called Tritanomaly, or Tritanopia which is not a type of what is commonly referred to as red-green color blindness, but is also a form of color vision deficiency. EnChroma glasses are designed to address forms of red-green color blindness and are not intended to assist the vision of people with Tritan-type deficiency. Fortunately, most cases of color blindness respond well to EnChroma spectral lens technology, enabling the perception of bright, vibrant color.