A recent study shows that blindness results in a permanent state of pain hypersensitivity, which is manifested, in particular, by a hypersensitivity to thermal stimuli.

One of the biological functions of acute pain is to prevent injury. Vision plays a critical role in this function, as it allows a person to detect and avoid potentially hazardous situations. But what happens in people who are blind? A recent study conducted in Italy and in Denmark indicates that they compensate for the absence of vision with a heightened vigilance for pain.

The three experiments conducted on blind people and people with normal vision consisted in measuring their pain threshold and the detection thresholds for warmth and cold perceptions. The results showed that, compared to sighted people, congenitally blind people had lower heat pain thresholds, found heat pain stimuli to be more painful and had increased sensitivity to cold pain stimuli.

“We have shown that the absence of vision from birth induces a hypersensitivity to painful stimuli, lending new support to a model of sensory integration of vision and pain processing,” explained Dr. Ron Kupers, from the University of Copenhagen, Denmark.

Sources:

http://www.sciencedaily.com/releases/2013/11/131101125413.htm

http://www.painjournalonline.com/article/S0304-3959(13)00275-3/abstract