PHPV is a developmental abnormality of the eye which occurs in the puppy embryo at about 4-5 weeks of age after conception. Blood vessels which help develop the lens of the eye are not reabsorbed as they should be. This results in deposits on the lens which can result in mild vision impairment to severe (blindness) depending on the grade or severity of the condition.

What are the signs or symptoms?
It is very difficult to pick up signs of impaired vision in young puppies but the condition in its severe form can be diagnosed by a veterinary ophthalmologist as early as 4 weeks of age, although it may be more readily detected when the puppy is older (8-12 weeks). What treatment is available? This condition is not readily treatable. If the vision impairment is mild, the dog may live a good quality lifestyle by compensating with its acute sense of hearing and smell.
Severely affected dogs can undergo specialist ophthalmological surgery but this is extremely delicate (and expensive) surgery with no guarantees of full recovery of vision.

How do I avoid buying a dog with PHPV?
Reputable breeders should be knowledgeable about this condition and be able to give you veterinary documentation that the parents of the puppies have been screened for this disease. Ideally they should also have had the litter screened for PHPV. If this is not the case, you can negotiate having this done before you purchase a puppy. The screening simply involves a veterinarian ophthalmologist dilating the dog’s pupil with some painless eye drops before looking into the eye with specialised equipment to examine the lens. This examination will detect severe PHPV but may not detect mild cases at this young of an age. If you plan to breed your dog, it is recommended to have it screened for PHPV again at 18 months of age.