hi sammy
the (ah2),ab2),ad2). just means what breed record supplement book they appear in, year ect)
gpra -means generalised progressive retinal athrophy
cpra- means central progressive retinal athrophy
the test is done at a specialist eye clinic under the bva/ kennel club eye scheme( its the bear min really) , they put some dye in the eye, and look at the eye under a magnifing class thing.