A large study suggests that men who take common erectile dysfunction (ED) drugs may have a slightly lower risk of developing certain types of glaucoma, a serious eye disease that can lead to vision loss.

Researchers looked at health records from more than 47,000 men aged 40 and older with ED. About half had taken phosphodiesterase type 5 (PDE-5) inhibitors, such as Viagra, Cialis, and Levitra, while the others had not. The researchers followed both groups for about 3 years.

Men taking these medications were somewhat less likely to develop warning signs of glaucoma, as well as open-angle glaucoma, the most common form of the disease.

“The association is likely vascular in origin, as PDE-5 inhibitors enhance [nitric oxide-cyclic guanosine monophosphate] signaling, improving ocular blood flow and optic nerve perfusion,” concluded Abdelrahman M. Elhusseiny, MD, of the University of Miami, and colleagues in a presentation at the Association for Research in Vision and Ophthalmology (ARVO) meeting.

After One Year

• About 6.5% of PDE-5 users were considered at risk for glaucoma, compared with 9.7% of non-users.

• About 2.1% of PDE-5 users developed open-angle glaucoma, compared with 3.2% of non-users.

After Three Years

The differences became smaller over time but remained significant after 3 years:

• 11.2% of medication users versus 12.1% of non-users were at risk for glaucoma.

• 3.9% of users versus 4.3% of non-users developed open-angle glaucoma.

Improving Blood Flow

Researchers think these drugs may help protect the eyes because they improve blood flow and may have protective effects on nerve tissue. PDE-5 inhibitors are already used not only for erectile dysfunction but also for conditions like pulmonary hypertension.

However, this study does not prove that the medications prevent glaucoma. Because it was based on medical records rather than a controlled clinical trial, other factors could explain some of the differences. For example, men taking these medications may differ in overall health, healthcare access, or lifestyle habits.

The findings are encouraging but preliminary. Experts say more research, especially randomized clinical trials, is needed before these drugs can be recommended to reduce glaucoma risk. People should not take ED drugs solely for eye protection without medical advice.

This story was originally published by Men’s Journal on May 8, 2026, where it first appeared in the News section. Add Men’s Journal as a Preferred Source by clicking here.