PRA is a genetic condition caused by several different genes. One of them, rdAc, is frequently found in siamese and oriental cats. In January 2011 at Sundsvall cat show Jaana Jyrkinen mentioned a study that had been done in Finland where they found that about 30 % of our cats are carriers or affected of this genetic condition. In August the same year SVERAK had introduced a breeding programme. According to this programme SVERAK members who breed siamese/oriental/seyschellois are not allowed to mate two carriers. Carriers are only allowed to mate carriers (N/rdAc) with free (N/N) individuals. Affected (rdAc/rdAc) are not allowed to be used for breeding, not even with free (N/N) individuals. It is therefor safe to say that no, or very few, cats sold in and from Sweden are affected by PRA.
PRA causes the retina to athropy, which leads to blindness. It is a slow process and a cat can be very good at compensating for loss of eye sight. PRA is not the only disorder that causes blindness, but it is easy to prevent now that we have inexpensive tests available to us.