How is progressive retinal atrophy (PRA) diagnosed?

• A. History
• B. Maze testing
• C. Electroretinogram
• D. Genetic testing

Answer: (C)

PRA is a retinal dystrophy that gradually destroys photoreceptors, so the key is assessing retinal function directly. An electroretinogram provides an objective readout of how well the retina responds to light, capturing the activity of the rods and cones. In PRA, these responses diminish over time and can become reduced or absent, often before severe vision loss is obvious on exam. This makes the electroretinogram the most reliable test to confirm PRA and to monitor disease progression.

History and clinical signs can raise suspicion—owners may notice night blindness or a gradual decline in vision—but they’re not definitive on their own because many other eye conditions can produce similar symptoms. Genetic testing is helpful for confirming known breed-specific PRA mutations and for guiding breeding decisions, but not all PRA forms have an identified genetic cause. Maze testing isn’t a recognized diagnostic tool for PRA.