Persistent Pupillary Membrane in Dogs
What is PPM in Dogs?
Persistent pupillary membrane (PPM) is an ocular disorder characterized by pigmented tissues on the eyes. The condition is a result of remnant mesodermal tissues that usually disappear during the development of the pupils. PPM is most common in Basenjis, chow chows, Welsh corgis, and mastiffs.
There are four known types of PPM: tissues located from iris to iris, iris to lens, iris to cornea, and a free-floating variant involving the iris and anterior eye chamber. The severity of PPM depends on the strand distribution of the vascular tissue.
PPM is a normal phase of the developmental process, which usually wears off when dogs are 4-5 weeks of age. Owners should only seek medical advice if the condition causes visual impairment in their pets beyond the developmental age.
The condition may be identified by white spots found on the eyes. Some cases involve cornea opacity leading to a clouded appearance. In severe cases, the inner layers of the cornea may be damaged by the adhesions, causing edema (fluid build-up), which might give the eyes a bluish hue.
Some cases of PPM may cause impaired vision or blindness, especially when membranes are attached to the delicate regions of the cornea.
The condition is difficult to diagnose in puppies and smaller breeds. Puppies may be born blind in severe cases of PPM.
Vets might request the medical history of your pet, which includes the owner’s observation of the pet’s visual abilities, and hereditary information. Dilating eye drops are applied before careful examination of the affected animal’s eyes with the use of specialized diagnostic instruments.
Your vet might provide a referral letter to a qualified vet ophthalmologist for a second opinion in serious cases of visual loss.
The condition usually does not require any treatment, with most minor cases (iris to iris, and iris to lens) resolving on their own in time. Cornea-associated cases, however, are known to gradually worsen eyesight and eventually cause blindness. In such cases, vet ophthalmologists are likely to recommend options for surgical intervention.
PPM is usually untreated unless it presents a direct threat to your pet’s vision. In such cases, vets may recommend cataract surgery that costs around $3,400 – $3,800 for both eyes, depending on the complexities of the procedure.
Home Care and Management
Pets with PPM do not require special care unless they are recovering from an eye procedure. Recovering pets should be kept safe from sharp edges of furniture and other hazards. Outdoor activities should be limited until your pet is fully recovered.