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Peptide eye drops may help protect vision

Photoreceptor cells (red) and supportive retinal pigment epithelial cells (green), imaged in a living human eye using adaptive optics. Tam et al., Investigative Ophthalmology & Visual Science August 2016, Vol.57, 4376-4384. doi: https://doi.org/10.1167/iovs.16-19503.

People born with a group of rare eye diseases called retinitis pigmentosa lose vision over time, with symptoms often starting early in life. Vision loss comes from the loss of cells in the retina, the light-sensitive tissue at the back of the eye. While promising therapies are under development, there is no cure or targeted way to protect the retina. One reason is that the disease can be caused by mutations in more than 100 different genes, making drug development a challenge.

In search of promising new options, an NIH-funded team led by Dr. S. Patricia Becerra ar �鶹��ý’s National Eye Institute has been studying a protein naturally found in the eye called pigment epithelium-derived factor (PEDF). Earlier studies suggested PEDF protects light-sensitive photoreceptor cells in the retina. A PEDF-inspired treatment, then, might hold promise for slowing or preventing vision loss with different underlying causes. But there was a problem. The full PEDF protein was too large to reach the retina at the back of the eye through a non-invasive eye drop.

To get around this, the team . They hoped these might provide protection similar to the full protein while remaining small enough to move through eye tissue. In a new study, they tested two types of eye drops containing a PEDF peptide in mouse models of retinitis pigmentosa. Their findings appeared in Communications Medicine on March 21, 2025

The team found that the peptides could reach the retina within an hour after drops were applied to the eye surface. In two different mouse models of retinitis pigmentosa, daily treatment with the peptide eye drops slowed the loss of light-sensitive cells and vision loss in young mice.

To find out if the approach might hold promise in people, the researchers tested the peptides in human retinal organoids—retina-like tissue grown in a lab dish. The organoids were first exposed to harsh chemicals, including cigarette smoke extract. This causes the rapid death of photoreceptor cells. Treatment with the peptide kept many more of these cells alive. Together with the findings in mice, the results offer proof of concept that a peptide eye drop could slow damage to the retina from genetic conditions or stress caused by chemical exposures or normal aging.

Gene therapies are now under development for many types of retinitis pigmentosa. With further study, PEDF-derived eye drops might help protect the retina and vision in people waiting for gene therapies to become clinically available. This approach also holds promise for protecting against age-related damage to the retina in people at risk for macular degeneration, the leading cause of vision loss in people over age 50.

“While not a cure, this study shows that PEDF-based eye drops can slow progression of a variety of degenerative retinal diseases in animals, including various types of retinitis pigmentosa and dry age-related macular degeneration,” Becerra says. “Given these results, we’re excited to begin trials of these eye drops in people.”