Eyedrops that lower pressure inside the eye can delay the onset of glaucoma, the second-leading cause of blindness, according to new research that should influence the way many at-risk patients are treated.

The drops were used to treat a condition called ocular hypertension, in which fluid in the front chamber of the eye doesn’t drain properly and pressure builds up. When the pressure rises sufficiently, it can press on the optic nerve and kill cells responsible for vision, crossing the threshold to become glaucoma. Age also contributes to glaucoma risk.

By intervening with medication in patients with elevated eye pressure readings, doctors reduced by more than 50 percent the number of cases that developed into open-angle glaucoma after five years.