Trish - my dog Pippin had cataract surgery on both eyes before he was 3 years old. Merry, his half-sister also has cataracts. I go back this coming may to my eye veterinarian to see if her cataracts have grown or not. Pippin is doing great after surgery. In fact, he is more outgoing now, probably because he can see!
As Sandy (Woodhaven) mentioned, cataracts look like very cloudy eyes. So if you are seeing a white spot, that is probably not a cataract.
Charleen and Cav's: Pippin (ruby male), Merry (b&t female), Luke (blenheim male) & Jolly (tri male puppy)