
Hi
I think I can help with the information on eye drops at testing, I have been running eye testing with Prof Peter Bedford for the last 27 years, (this will be the 28th year!). In that time I have seen all the different tests done and have even been asked to write about them in a number of magazines.
The drops put into the eyes for a gonioscopy test for glaucoma are put in immediately before the gonioscopy test. They are a mild local anesthetic to numb the surface of the eye, which allows the examiner to place a pressure cap or lens directly onto the eye to test for pressure levels or to examine the drainage angle.
The drops put into the eyes for a PRA, HC or other standard test are totally different and they dilate the dogs pupil completely so that the examiner can see clearly into the back of the eye and view the retina. These drops take approximately 20 minutes to work.
If you are planning on having both tests done get the gonioscopy done first, as the other drops will make it impossible for the examiner to test for glaucoma predisposition.
If a vet ever gives a sedative or general anesthetic for a glaucoma test, you will get a false result. All sedatives and general anesthetics relax the muscles and ligaments in the eye so the drainage channel will close down on itself and pressure in the eye will drop, so you need to make sure the dog is wide awake.
With glaucoma testing (gonioscopy) the part of the eye being examined is the ligaments through which the excess fluid drains from the eye. If the gap between the ligaments is too narrow, due to thickened ligaments, or is mishappen in some areas the dog has a predispostion to glaucoma. The degree of predisposition depends on how band the remaining drainage area is. This like judging dogs can be subjective and in very mild cases one panelist might pass the dog but another may well fail it.
Originally there was a grading scheme for gonioscopy but it was dropped when it was realised that some breeders would say that their dog was ok to bred from even though the result was not good. So now officially most breeds now have a pass or fail result available.
In flatcoats we had a grading system of 0 (pass) to 5, but then a vet who is NOT a specialist at a flatcoat meeting told breeders attending that "It may well be that is is normal for flatcoats to score a grade one or two". Unfortunately this was misunderstood and some people left that meeting thinking that if a grade one or two was normal then it was perfectly OK to breed from a grade three or four! The vets poor choice of words was stupid, and as the talk was on first aid I had no idea why they were talking even giving advice on glaucoma! What the vet had meant was that it might turn out that most flatcoats would score a grade one or two, but these were still failures. As it has turned out they have a majority of 0 (pass) scores.
One thing must always be kept in mind in any breed which suffers from glaucoma, and that is that it is the most horibly painful way for a dog to go blind! So test your dogs and if they fail make sure you know the symptoms of glaucoma in dogs, because you will probably have less than 24 hours from onset to get your dog operated on to save it's sight and more importantly to save it almost unimaginable pain.