THe link to the KC/BVA/ISDS eye scheme is here.
It explains about eye testing, the different conditions that affect different breeds and the importance of removing affected dogs from breeding programmes.
Not all breeds must be tested but there are two schedules one of which is regarding breeds which have known issues and others which are breeds under investigation.
GSD are on Schedule A for HC (Heriditary Cataract). This condition as well as others requires a yearly screen; others may only need one for life.
Very very few GSD breeders have their dogs eye screened.