
The litter testing is all recorded on one sheet. What I would watch for is the breeder who tests half the litter and not the other half. There is a well known breeder in a breed I know who does just that. She selects the most likely show potential pups and eye tests them. The rest she does not test, but always advises her buyers that she only breeds from tested stock therefore it would not be likely for any puppy to have an eye problem.
When you go to see the breeder, you could ask for a contract of sale for the puppy, in which the breeder must state whether or not your puppy has been tested and what the result is. The breeder I have mentioned above is the only one I know who does not use the testing scheme properly, but from many years of experience with breeders who test regularly I have found that they are an honest bunch who are really trying to do the best for their breeding stock and the puppies they are breeding.
A responsible and good breeder will show you a copy of the litter screening test certificate and may even have a photocopy you can keep. Eye testing a litter can be done as soon as the pups are big enough. In some breeds this might be as young as 5 weeks, and the eye tests for CEA can be done up to the age of 14 weeks, after which the dog is considered to be too old and can give a normal result although was slightly affected at a younger age. The reason is that the "holes" in the retina which is what CEA basically is can heal over as the dog grows, so the dog is termed a "go normal" in some breeds.
You could always tell the breeder you want to have the puppy checked out yourself, and take it to an eye testing session as soon as you get it. You would need to go to a specialist eye examiner, such as Prof. Peter Bedford for this examination. Specialists often do the examinations at sessions arranged by breeders and clubs, these are advertised in Dog World or Our Dogs news papers. I run three sessions each year in Haddenham Bucks and always advertise in the canine press. (Your Dog magazine got the date wrong this year, instead of printing the 17th they said it was the 14th of Feb!).