Exploring New Treatments for a Painful Eye Disease – Corneal Endothelial Dystrophy

Dogs are susceptible to a painful eye condition known as corneal endothelial dystrophy (CED). In this disease, the cells of the innermost layer of the cornea, the clear part of the eye, deteriorate and lose their important ability to maintain the fluid balance and clarity of the cornea. This results in corneal swelling and vision loss. Painful corneal ulcers can also form, potentially leading to infection and even eye removal.

The only definitive treatment for CED is corneal transplantation, which is rarely done in veterinary medicine due to the risk of rejection, lack of donor tissue, and cost. Veterinarians typically focus on palliative treatments to reduce corneal swelling and manage corneal ulcers.

To explore new treatments for CED, researchers at the University of California, Davis looked to a class of drugs called ROCK inhibitors. Ripasudil is a topical ROCK inhibitor that led to stable or improved disease in more than 60% of treated CED eyes in a recent study. Unfortunately, this drug is not commercially available in the United States and must be given four times per day. Building on this research with funding from the AKC Canine Health Foundation (CHF) (CHF Grant 02696: Efficacy and Safety of Netarsudil for Canine Corneal Endothelial Dystrophy), researchers tested another ROCK inhibitor, netarsudil, that is FDA-approved for the treatment of glaucoma in people and only requires twice daily administration.

To assess netarsudil’s effectiveness in treating canine CED, several measures of corneal health were monitored in dogs receiving either the medication or a control solution over 4-8 months. All dogs developed some degree of conjunctival hyperemia (dilation and redness of the conjunctival blood vessels) while receiving netarsudil, but it was never severe enough to require treatment and other adverse reactions were rare. While well-tolerated, corneal health measurements did not significantly improve during netarsudil treatment.

Researchers compared the results from this netarsudil study with their previous study on ripasudil. Even though ripasudil requires more frequent application, it does appear to be a better choice for treating CED in dogs. 

Studies like this are important to develop proven, evidence-based treatments for canine diseases like CED. Veterinary medicine can often borrow knowledge and medications used in human medicine, but not always. This study demonstrates that research focused specifically on canine disease is needed to ensure a healthier future for our beloved dogs. CHF and its donors remain committed to finding and funding such studies with the most potential to advance the health of all dogs. Learn more about this important work at akcchf.org/research.