In October 2008, when he was almost 2 years old, Trevor was given a routine Optigen screening for PRA. PRA (progressive retinal atrophy) is a genetically transmitted disease that leads to blindness. Even though PRA is extremely rare in Golden Retrievers, Trevor was found to be "affected" with prcd-PRA.
From the Optigen website:
PRA refers to a group of diseases that cause the retina of the eye to degenerate slowly over time. The result is declining vision and eventual blindness. “prcd” stands for “progressive rod-cone degeneration” which is the type of PRA known in several breeds.
Trevor had no symptoms, so to confirm his "affected" status, his opthamologist did an ERG test. An ERG test can find physical signs of PRA years before it's detectable by any other means. The test confirmed Trevor's "affected" status. To date his CERF is clear.
See PRA Research for a desciption of the research I've done, as well as links to scientific research.
Trevor's Supplement Regime.
Most people seem to think that prcd-PRA in Goldens is likely to be similar to prcd-PRA in labs. According to Wikipedia, the typical progression for labs is: "Night blindness by four to six years old, blind at six to eight years old. "
There is one caveat, and that is that PRA affects every individual differently. Even among littermates, the age of onset can vary by years, and the disease can progress at vastly different rates. No one knows why these variations occur.
Once prcd-PRA was discovered in a Golden (see Daphne's Story), Gerry Clinchy and Mardi Closson worked with Optigen to get a prcd-PRA test for Golden Retrievers. Thanks to their efforts, Golden breeders now have the tool they need to keep this disease from spreading any further.