There may be a correlation between a person’s preferred sleep position and the health of his or her meibomian glands, reports Ophthalmology Times.

Speaking at ASCRS 2016, Dr. Alevi said meibomian gland dysfunction (MGD) is thought to be a leading cause of dry eye, and often presents with similar symptoms.

But in his practice in New York, Dr. Alevi and his colleagues began to notice a difference among the patient complaints—and that people who were side sleepers tended to have more symptoms in the morning than people who slept on their backs.

“We wanted to examine the correlation between sleep position with the symptoms of dry eye, MGD, and irritation,” said Dr. Alevi, of Ophthalmic Consultants of Long Island, Rockville Centre, NY. “As clinicians, we already know how MGD is defined and how it can help characterize changes in the tear film. But it’s unclear what effect some non-obvious habits may have.”