The drug class showed nothing; sildenafil alone doubled the risk
Pooling five observational studies of sudden vision loss in one eye, the class as a whole showed no significant rise in risk. The sildenafil subgroup inside it rose 2.25 times.
What the study found
One analysis, a null for the class and a doubling for sildenafil
Pooling five observational studies of non-arteritic anterior ischemic optic neuropathy, a rare and usually permanent loss of vision in one eye, the drug class as a whole showed no significant rise in risk. The sildenafil subgroup within that same pooling did, at 2.25 times.
The caveat · Not adjusted for vascular disease
Five observational studies, no randomised evidence, and the risk ratios are not adjusted for the vascular disease that causes both erectile difficulty and this kind of vision loss. The subgroup figures rest on very few cases, because the condition is rare and hard to diagnose in the first place.
What we don't know
Pooled studies found no clear rise in sudden optic-nerve damage for the drug class, yet sildenafil alone came out at about twice the risk. Which holds is open, against a base rate of 2.5 to 11.8 cases per 100,000 men over 50 a year.