FRIDAY, Feb. 7, 2020 (HealthDay News) -- Missing just one eye doctor appointment can result in vision loss in older adults with macular degeneration, a new study warns.

Age-related macular degeneration (AMD) is a leading cause of vision loss in the elderly, and these findings show the need for patients to keep all scheduled appointments with an ophthalmologist, the University of Pennsylvania School of Medicine researchers said.

For the study, the investigators analyzed data from nearly 1,200 AMD patients across the United States who were part of a two-year clinical trial of anti-VEGF (intravitreal anti-vascular endothelial growth factor) treatment. It involves injections into the eye by a doctor.

Patients were required to visit an ophthalmologist once every four weeks, for 26 visits. Not all visits involved injections.

The study found that patients who missed scheduled appointments had greater declines in vision, with each missed visit associated with an average visual acuity letter score decline of 0.7.

Compared to patients who made all visits, those who averaged 36 to 60 days between visits lost 6.1 letters, and those who went more than 60 days between visits lost 12.5 letters, according to the study published online Feb. 6 in JAMA Ophthalmology.

These findings show the need to "reframe" how doctors think about treating AMD patients, said study author Dr. Brian VanderBeek, a professor of ophthalmology.

"Let's worry less about predicting a specific number of injections a patient needs and more about getting them into the doctor's office," he said in a university news release.

AMD is the leading cause of permanent vision loss among Americans over age 50. About 1.8 million people in the United States have AMD and another 7.3 million are at risk for the disease, according to the U.S. Centers for Disease Control and Prevention.

More information

The U.S. National Eye Institute has more on age-related macular degeneration.