TUESDAY, June 19 (HealthDay News) -- A daily dose of java may help prevent a form of severe eyelid spasm that can cause a person to become "blind," a new study suggests.

In people with primary late onset blepharospasm, the eyelid muscles contract uncontrollably and cause involuntary blinking. In extreme cases, people are unable to prevent their eyelids from clamping shut and, despite having healthy eyes, they become functionally blind, according to background information in the study.

The new study included 166 Italian patients with primary late onset blepharospasm and two control groups -- 187 people who were relatives of the patients and 228 people with another kind of facial spasm disorder -- who were asked about their coffee consumption.

A team at the University of Bari found that just one to two cups of coffee a day helped protect against late onset blepharospasm and that increased coffee consumption also delayed onset of the condition -- 1.7 years for each additional cup of coffee per day.

The study authors noted that previous research has suggested that caffeine may help prevent Parkinson's disease by blocking adenosine receptors, and the same mechanism may play a role in coffee's protective effect against primary late onset blepharospasm.

"Considering that the caffeine content of a cup of Italian coffee (60-120 milligrams) is similar to the average content of a cup of American coffee (95-125 milligrams), the protective effect on the development of blepharospasm may be exerted at caffeine doses greater than 120-240 milligrams, comparable with the caffeine doses suggested to be protective against Parkinson's disease," the study authors wrote.

Their findings were published online June 19 in the Journal of Neurology, Neurosurgery and Psychiatry.

Previous studies have suggested that smoking helps protect against blepharospasm, but the authors said they found no evidence to support that theory.

More information

The U.S. National Eye Institute has more about blepharospasm.