Carmen had her ophthamologist appointment today at Animal Eye Specialists in West Bridgewater. The tech tested her tear production, used a flourescent wash to look for scratches, and also blew air at her eyes to test for glaucoma. I was starting to second guess myself and feel like maybe I was silly in suggesting Carmen see an eye specialist – maybe we should have gone to the regular vet first. Then the vet came in.
After taking a look at her eyes and asking about the discharge he told me she has conjunctivitus. Oh! That was unexpected. Then he spent quite a bit of time examing her eyes with something called an indirect ophthalmoscope (I am pretty sure). It was quite an interesting contraption. He said her retinal arterioles are smaller than they should be and that is a sign of PRA. Progressive Retinal Atrophy. He then had Carmen walk about the room with the lights on, dimmed, and off. You could see how confused and hesitant she was in the dim light – almost more so than with the lights off completely. Or perhaps it was just more noticeable to me. One of the first signs of PRA is night blindness.
Now it begins to make sense that Katrin would see the signs that she was having vision problems at the indoor – the lighting isn’t perfect.
The bad news is that there is nothing to be done for PRA. It is progressive. Carmen will go blind. The good news is that there is anecdotal evidence that Ocuvite might slow the progression of PRA. Ocuvite is an OTC vitamin which Carmen will be getting a ½ tab of for the rest of her life! PRA is hereditary. The vet said Carmen probably had micro-macular signs at six weeks.
Ugh, it sucks. I thought this appointment would be paying for peace of mind. That the vet would say she is near sighted or far sighted. Instead the diagnosis is one of my worst case scenarios. More good news is that the progression is typically pretty slow. Carmen can play agility until she becomes a hazard to herself! Hopefully quite some time. I will just need to be a very conscientious handler and make sure the lighting is good in the venues we play in.
I have sent an e-mail off to the breeder and will follow up with a phone call.
Progressive retinal atrophy, or PRA as it is frequently termed, is a long recognized, hereditary, blinding disorder. It is inherited as a simple autosomal recessive in most breeds. The first modern description of this problem was in Gordon Setters in Europe, in 1911, but since then PRA has been recognized in most purebred dogs. Millichamp et al. In 1988, described PRA in Tibetan Terriers. Also in 1988, it was found that PRA in Cockers, Poodles and Labradors was the result of a mutation at the same gene locus in all these breeds.
PRA is a disease of the retina. This tissue, located inside the back of the eye, contains specialized cells called photoreceptors that absorb the light focused on them by the eye’s lens, and converts that light, through a series of chemical reactions into electrical nerve signals. The nerve signals from the retina are passed by the optic nerve to the brain where they are perceived as vision. The retinal photoreceptors are specialized into rods, for vision in dim light (night vision), and cones for vision in bright light (day and color vision). PRA usually affects the rods initially, and then cones in later stages of the disease. In human families, the diseases equivalent to PRA (in dogs) are termed retinitis pigmentosa. (This page has a good picture of normal retina versus a mid-stage PRA retina.)
3 weeks ago