University of Pittsburgh and UPMC Vision Institute Researchers Explore “Living Eye Drop” for Corneal Healing
March 19, 2026
A team of researchers from the University of Pittsburgh Department of Ophthalmology and the UPMC Vision Institute recently published a proof-of-concept study in Cell Reports showing that genetically modifying a type of naturally occurring bacteria can support corneal wound healing, opening the door for further exploration of "living eye drops” for corneal abrasions and other vision conditions.
Anthony St. Leger, PhD, associate professor of ophthalmology and immunology at Pitt and the Vision Institute, served as senior author on the study. Dr. St. Leger holds a doctorate in Immunology from the University of Pittsburgh and completed his postdoctoral fellowship at the National Eye Institute. His lab studies the ocular microbiome, the community of microorganisms like bacteria, fungi, and viruses that live within the eye.
Using mouse models, Dr. St. Leger and his team – which included fellow Pitt researchers Jackie Shane, PhD, Matthew Evans, Yannis Rigas, and Robert Shanks, PhD – demonstrated that Corynebacterium mastitidis (C. mast), a harmless bacterium that lives under the eyelid, can be engineered to secrete cytokine interleukin10 (IL10), a small protein that regulates inflammation. The study revealed that mice treated with genetically modified C. mast healed faster than those treated with regular bacteria or saline.
Although not yet being studied in humans, the genetic modification of C. mast could lead to the development of more sustainable treatments for corneal wounds, severe dry eye, and other inflammatory conditions of the ocular surface, which currently require multiple applications of medicated eye drops throughout the day.
“More research is certainly needed, particularly to determine how to deactivate the protein once treatment is no longer necessary,” says Dr. St. Leger. “But the findings in this study are promising, and could open the door to the development of “living” medications for a range of vision conditions.”
The work in this study was supported by the National Institutes of Health (R01EY032482, U24EY035102, T32EY017271, EY036686 and CORE Grant P30 EY08098), the Hillman Innovation Exploratory Award, the Eye & Ear Foundation of Pittsburgh and Research to Prevent Blindness.
