Coffee drinking protects against an eyelid spasm that can lead to blindness, according to findings of a multi-centre case study published online ahead of print in the Journal of Neurology Neurosurgery and Psychiatry.
Researchers claim that people who drink coffee are less likely to develop primary late-onset blepharospasm, a dystonia in which the eyelid muscles contract uncontrollably.
In extreme cases sufferers are rendered functionally blind despite normal vision because they are unable to prevent their eyes from clamping shut.
The Italian study involved 166 patients with primary late-onset blepharospasm, 228 patients with hemifacial spasm (a similar muscle spasm that usually begins in the eyelid muscles but then spreads to involve other muscles of the face) and 187 people who were relatives of patients. The second two groups acted as controls.
Regression analysis was also used by the researchers to observe the relationship between coffee drinking and smoking on the development of blepharospasm.
Findings suggest that the effect was proportional to the amount of coffee drunk and one to two cups per day were needed for a protective effect. The age of onset of the spasm was also found to be later in patients who drank more coffee - 1.7 years for each additional cup per day.
Previous studies have suggested that smoking protects against development of blepharospasm, but the authors said: 'Our findings raise doubt about the association of smoking and blepharospasm but strongly suggest coffee as a protective factor.'