A new gene therapy developed by University of Florida Health researchers stops vision loss and improves sight in dogs — a key step toward testing the treatment in people affected by a group of genetic eye disorders.

The therapy uses a small, harmless virus to deliver genetic material that blocks and reverses the effects of retinitis pigmentosa, a group of inherited diseases that kills light-sensitive cells in the retina. The gene delivery vehicle, known as an adeno-associated virus, or AAV, vector, is unique for its sight-saving double punch: It silences the mutant rhodopsin gene that causes retinal degeneration while also delivering a normal, replacement copy of the gene. The AAV therapy saved photoreceptor cells and prevented vision loss among the dogs in the study. The findings are published today in the Proceedings of the National Academy of Sciences