Rat Research Points to Treatment to Halt Blindness From Glaucoma

Scientists peering deep into the eyes of rats have discovered a new target for treating glaucoma: Blocking a chemical called nitric oxide may slow, if not prevent, the blindness.

So far, it has worked only in rats. But the research is so promising that Missouri scientists are talking with pharmaceutical companies about trying to create a drug for glaucoma patients.

The discovery is “a completely different way of treating the disease,” explained lead researcher Arthur Neufeld, an ophthalmology professor at Washington University School of Medicine in St. Louis.

Glaucoma is the second leading cause of irreversible vision loss in the United States and the most common cause among black Americans. An estimated 3 million Americans have glaucoma, and 120,000 are blind as a result.

In glaucoma, pressure inside the eyeball increases to high levels because eye fluid doesn’t drain properly. Eventually, that pressure damages the optic nerve and progressively eats away vision.

Until now, all treatment has been aimed at easing that pressure, either with eye drops or surgery.

But Neufeld discovered an enzyme called NOS-2 that makes destructive amounts of nitric oxide. And he found that rats given a drug called aminoguanidine, which inhibits NOS-2, lost less than 10% of their retinal cells compared with 36% of untreated rats.