Treating Corneal Ulcers

The cornea, the clear tissue at the front of the eye, provides a window for the horse to see through and focuses light on the retina, making it essential for proper vision. Wounds in the cornea, or corneal ulcers, are common in horses. They have several potential causes, including injury, infection, and autoimmune disease. If not treated quickly with the correct therapy, they can affect vision permanently and even result in the loss of the eye. 

The good news is that the cornea has significant capacity to heal. With appropriate treatment, small, superficial corneal ulcers often resolve within one to two weeks. Ulcers that are deeper in the cornea or otherwise more complicated may require much longer treatment, and could require surgery. The appropriate therapy depends  on the cause of the ulcer, along with any secondary factors.

Medical therapy

Picture of a subpalpebral lavage (SPL) catheter leading into horse's eye.
A subpalpebral lavage (SPL) is placed to make it easier to administer medications to the eye.

Medical treatment may consist of various drugs and topical therapies. When multiple treatments are required several times a day, a subpalpebral lavage (SPL) may be placed to make it easier to administer medications. A SPL is a small catheter placed through the eyelid that allows delivery of medication to the surface of the eye through long tubing braided into the mane. A port at the end of the tubing, near the base of the neck, allows medication to be administered far away from the eye. Horses typically tolerate this system much better than applications directly into the eye. At UC Davis, the use of SPLs has facilitated the successful treatment of complicated cases that would have been nearly impossible to treat otherwise. 


Surgery for corneal ulcers may be required to remove unhealthy tissue from the eye and provide structural support to the cornea (which is less than 1mm thick in a horse). Surgical grafts utilizing natural or synthetic/biosynthetic tissues may be used to increase the blood supply to the area and promote healing. Procedures for corneal transplantation are still evolving, but to date have largely been successful for preserving vision.