Men who wear ties could be more at risk of developing glaucoma, the potentially blinding eye condition.
Researchers in America have discovered that ties worn too tightly increase blood pressure inside the eye in the space of a few minutes.
Raised blood pressure inside the eye is the most important known risk factor for glaucoma, say Dr Robert Ritch and colleagues from the Glaucoma Service at the New York Eye and Ear Infirmary, reporting their findings in the British Journal of Oncology.
They believe the effect may be caused by constricting the jugular vein, which raises blood pressure in the eye.
Dr Ritch also said that wearing a tie during an eye test could lead to a falsely high reading of intraocular pressure or even a diagnosis of glaucoma itself.
"A tight tie can be considered a risk factor in men who prefer to wear tight ties, men with thick necks, and white-collar professionals," he said.