There are 3 types of cataracts –
The first 2 are those which dogs are either born with or develop in the first few years of life. They are both considered to be hereditary, most particularly in Schnauzers. All Schnauzers litters should be screened by an Ophthalmic Specialist between 6 and 8 weeks of age under the BVA Eye Scheme https://www.bva.co.uk/Canine-Health-Schemes/Eye-scheme/
Adult Schnauzers are screened annually under the same scheme.
Bouviers have no formal requirement for eye screening but some breeders chose to do this voluntarily with their adults prior to breeding.