A longevity startup has dosed its first patient with a drug to reverse age-related sight loss.

Life Biosciences is testing its ER-100 drug, which the company claims has restored vision in monkeys, for safety and side effects in a study of around 18 adults over the next year.

It will be targeting patients with glaucoma and NAION, two conditions that cause damage to crucial cells in the optic nerve, which transmits visual information from the back of the eye to the brain. ER-100 is designed to rejuvenate those cells so that they work again and restore sight.

It is the first-ever cellular-rejuvenation therapy using this technology to receive FDA clearance to enter human clinical trials, and hence the first chance to test whether the technology can “ameliorate human disease,” according to Life Biosciences cofounder David Sinclair, who is also a professor of genetics at Harvard Medical School.

Aging biology—understanding how the body’s cells and functions deteriorate over time—is at the root of longevity science. ER-100 is the focus of major interest across biotech for its potential to reverse cellular aging. Life Biosciences, based in Boston, says it is developing applications for its technology to tackle a host of age-related diseases in a variety of organs, like fatty liver disease.

“Our research has suggested that aging is driven in large part by the loss of epigenetic information, not irreversible damage. This clinical study represents the first opportunity to test whether restoring that information can ameliorate human disease,” Sinclair said.