Little is known about the heredity within most breeds. In fact, researchers and breeders suspected primary glaucoma only recently in some breeds. The incidence also varies by country because not all bloodlines are affected equally and bloodlines differ by country. For example, while English Cocker Spaniels are at risk in Great Britain, cases are not common among the breed in the United States, but glaucoma is common in the American Cocker Spaniel here, whereas American Cockers in England don't seem prone to it.

Research suggests the possibility of inherited glaucoma in some U.S. and British lines of the following breeds:

• Alaskan Malamute
• Basset Hound
• Beagle
• Bouvier des Flandres
• Brittany
• Chow Chow
• Great Dane
• Miniature and Toy Poodles
• Norwegian Elkhound
• Pefft Basset Griffon Vendeen
• Retrievers (Golden, Flat-Coated)
  
  
  
  
• Samoyed
• Shar-Pei
• Siberian Husky
• Spaniels (Cocker, English Cocker, Welsh Springer)
• Terriers (Sealyham, Smooth Fox, Standard Manchester, Welsh, Wire Fox, perhaps others)
• Welsh Corgi