Cerebral Achromatopsia & Color Vision
Recently, in the office over a one month span, two patients noted that they had lost their color vision. Both patients were in their late 50s and had previous strokes. The one called on a Friday morning from quite a distance from my office. I noted to him that he must contact his internist and have a CAT scan and also see a neurologist. He was going to call the office the following week and schedule an appointment and I haven't heard from him since. The second was a patient who came to the office with an aide, since he had some cognitive and physical issues. He noted that when he watches TV it is essentially black and white but with some vibrant colors, he can notice partial colors.
The reason that this condition is unusual and interesting is that color vision according to an eye doctor is from the rods and cones. BUT the actual part of the brain that brings that color to light is the occipital cortex. These patients that lose their ability to partially see or completely see color vision have had strokes in the visual cortex of the brain. In most cases, the still know their colors and can picture them in their mind but don't see them.
Upon testing the gentleman that was in my office, using my dropper bottle colors, he was able to describe the colors but noted in his lower right field that he did not see the colors. I researched this lack of color in the visual field and came upon the condition of Cerebral Achromatopsia. I have listed below two websites that fairly well describe the condition and will make further posting to this site upon further writings and research.
The photos at the top of the page were taken from the 2nd website listed below.
https://en.wikipedia.org/wiki/Cerebral_achromatopsia
http://www.macalester.edu/academics/psychology/whathap/ubnrp/visionwebsite04/achromatopsia.html
A simple slide presentation on color vision defects can be found at: