Tritanopic after Head Injury

• Posted by Daniel Flück on June 8th, 2006 filed in Academic

Divya from India asks me the following question. She tells a short story about acquiring color blindness after a heavy head injury. Here are the lines Divya sent to me:

my boyfriend suffered an injury while playin cricket recently and the optician diagnosed it as tritanopia..heres what happened..he was aplying and was kinda nauseous and he puked in his helmet and fainted and fell backwards and got a hard blow on his head from the bat and a whack from the ground at the back of his head again and got knocked out/fainted..he was out for almost an hour and when he regained consciousness he was colourblind…the optician said its tritanopia..and he can only see luminous stuff as in highlighters and violet stuff and other stuff appears gray…what i want to know is…is this permanent or is it temporary…and if it is curable how can it be done…

I will try my best to answer the above questions and give some more insights about acquired color blindness. As I am not a professional in the field of color vision professional help should be frequented for detailed clarifications.

Unfortunately color blindness can be caused by severe head injuries. By far the most occurences of color blindness are congenital. In very rare cases people with perfect color vision abilities can be affected by an impaired vision or color vision deficiency after a brain trauma, a stroke or some other kind of severe head injury.

Such vision deficiencies are caused by a damage of the optical cortex. Several cases are described in scientific papers but there are no results concerning the cause of the loss of color vision. Some speculate, that the patient’s abnormality arises from partial destruction of the chromatic mechanism. The case described by Divya above about an acquired tritanopia may also occur, if the rod-cone mechanism is damaged.

Unfortunately as much acquired color blindness as congenital color blindness are not curable or at least there are no methods known to this day. As an acquired color blindness is without much doubt caused by some damage in the optical cortex most likely there will be no cure in sight in the near future.

Also because most often a severe damage causes the color blindness, there is evidence to suggest that this trait will be permanent and not only a temporarly impairment.

Update: Please also read the comment of Peter. He is a vision scientist from UCSF and shares some more very interesting insights into the topic. Thanks Peter.

Further reading:
Traumatically acquired color vision defect

Related article:
Tritanopia – Blue-Yellow Color Blindness