People who have had shingles infection that affects the eyes may have a heightened risk of stroke, according to a new study. Ocular shingles is an infection of the eye and the skin around the eye caused by the same virus that causes chickenpox.

To reach the conclusion, researchers identified 658 people diagnosed with ocular shingles and 1974 without the infection. None of these people had a history of stroke at the beginning of the study.

During the one-year study, stroke developed in 8.1 percent of the people with shingles and 1.7 percent of the people without shingles.

The study found people with shingles were four-and-a-half times more likely to have a stroke compared to people without shingles. The results were the same regardless of age, gender, high blood pressure, diabetes, heart disease and medications.

"Shingles may represent a marker for increased risk of stroke," said Jau-Der Ho with Taipei Medical University in Taiwan.

The study also found the people with shingles were more likely to have ischemic stroke, such as a blood clot, and less likely to have hemorrhagic stroke, such as bleeding in the brain, compared to people without shingles.

Antiviral drugs are used to treat ocular shingles. The researchers found that there was no difference in the risk of stroke between people who received antiviral drugs and those who did not.