Penn Vet Researchers Map How a Common Blinding Disease Progresses in Dogs and Humans

A team of vision scientists at the University of Pennsylvania School of Veterinary Medicine (Penn Vet) has uncovered how a common inherited cause of blindness progresses over time, providing new insight that could benefit both canine and human patients.

In a new study in Experimental Eye Research, researchers from Penn Vet’s Division of Experimental Retinal Therapies (ExpeRTs) describe the first detailed, longitudinal characterization of progressive rod-cone degeneration (PRCD), one of the most widespread genetic causes of vision loss in dogs and a form of retinitis pigmentosa (RP) in humans.

RP is a group of inherited retinal diseases caused by mutations that disrupt photoreceptors, the light-sensing cells at the back of the eye, leading to gradual and irreversible vision loss. Symptoms often begin with night blindness in childhood and progress over time. While more than 120 genes have been linked to RP, PRCD affects more than 75 dog breeds and has long served as an important model for human disease.

Despite its prevalence, the precise pattern of disease progression has remained poorly understood.

“This disease was first described by one of my mentors, Dr. Gustavo Aguirre, 50 years ago,” said Valérie Dufour, DVM, DECVO, DACVO, assistant professor of Translational Ophthalmology at Penn Vet and senior author of the study. “Until now, we did not fully understand how it evolves over time.”

Tracking Retinal Degeneration Over Time

Using advanced multimodal retinal imaging, the research team followed a population of PRCD-affected dogs over time, allowing them to map how the disease unfolds.

They identified a highly consistent pattern of degeneration: retinal thinning that begins in the periphery and progressively advances toward the center. This spatial and temporal progression mirrors the clinical phenotype observed in human patients with PRCD-associated retinal diseases.

By defining this reproducible trajectory, the study provides a clearer framework for understanding how vision loss develops and for measuring it more precisely in both research and clinical settings.

“This work represents a significant step forward in our understanding of disease progression,” Dufour said. “The similarities between the canine model and human patients reinforce the translational value of these findings.”

A New Framework for Clinical Care

The findings are already informing patient care at Penn Vet’s Ryan Veterinary Hospital, where Dufour recently established a Retinal Health Clinic focused on diagnosing and managing inherited retinal diseases in dogs.

Using state-of-the-art imaging and functional testing, the clinic applies insights from the study to detect disease earlier and monitor progression more accurately in client-owned animals.

“Our goal is to bridge the gap between research and clinical care,” Dufour said. “By applying what we’ve learned, we can provide more accurate prognostic information and more personalized care for dogs affected by PRCD, while also supporting the development of effective therapies.”

A Collaborative, Translational Effort

The study reflects a long-standing, cross-disciplinary collaboration between Penn Vet and the Perelman School of Medicine’s Scheie Eye Institute, as well as international partners.

By establishing a detailed map of PRCD progression, this work strengthens the role of naturally occurring canine models in translational vision research and may help guide future strategies to preserve or restore vision in human patients with inherited retinal diseases.

Penn Vet authors are Valérie Dufour, co-first author Yu Sato; senior co-authors Gustavo D. Aguirre and William A. Beltran; Raghavi Sudharsan, Ana Ripollés-García, and Jennifer C. Kwok.

Perelman School of Medicine’s Scheie Eye Institute: Artur V. Cideciyan, Tomas S. Aleman, Alexander Sumaroka, Yinxi Yu, and Gui-Shuang Yang.

Hadassah-Hebrew University Medical Center, Center for Retinal and Macular Degenerations: Dror Sharon and Eyal Banin.