June 19 (Bloomberg) -- Coffee may help its drinkers keep their eyes open in an unexpected way, researchers said.

The beverage more commonly associated with elevated blood pressure and insomnia may help protect people from an eye disorder known as blepharospasm, according to a study published today in the Journal of Neurology, Neurosurgery and Psychiatry. The condition, caused by abnormal brain function, makes people blink incessantly and can leave them functionally blind.

Patients are currently treated either by surgically removing eyelid nerves or with drugs such as Allergan Inc.'s Botox, an injection that paralyzes facial muscles, according to the U.S. National Institutes of Health. A team of Italian doctors found that people who drank more than two cups of coffee a day delayed the onset of blepharospasm by 1.7 years for each extra cup.

The condition ``is quite similar to Parkinson's disease,'' said Giovanni Defazio, a professor at the University of Bari who led the study, in a telephone interview. ``In Parkinson's disease, it is well established that coffee and smoking have a protective effect.''

Researchers examined the coffee-drinking and smoking habits of 166 blepharospasm patients at five hospitals across Italy, with an additional 415 people serving as a control group. The data was compared with how old the patients were when they experienced their first uncontrollable blinking episodes.

Protective Effect

``Our findings raise doubt about the association of smoking and blepharospasm but strongly suggest coffee as a protective factor,'' the authors wrote in the U.K. journal.

Very little data exists about blepharospasm or its genetic and environmental causes, Defazio said. A recent study showed the disease affects about 133 people per million in Italy, he said.

Caffeine probably helps by blocking adenosine receptors, which can slow metabolic activity in the brain. Coffee consumption should be included in further research, Defazio and colleagues said.

``It is interesting to note that generally, people with spasms of the eye are advised to refrain from caffeine,'' Roger Cook, director of the Coffee Science Information Centre, an Oxford, England-based research group, said in an e-mail. The findings ``provide further evidence to support that coffee drinking in moderation is perfectly safe, and increasingly is being shown to confer some health benefits.''

The next step is to examine whether coffee has a similar role in preventing other muscle disturbances linked to blepharospasm, Defazio said.

The research was funded by a grant from the Italian Ministry for Education, University and Research.

To contact the reporter on this story: Alex Kuli in Budapest at akuli@bloomberg.net

Last Updated: June 19, 2007 05:47 EDT