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PPM

Issue Description
Persistent pupillary membranes are strands of tissue in the eye. They are remnants of blood vessels which supplied nutrients to the developing lens of the eye before birth. Normally these strands are gone by 4 or 5 weeks of age.
Other Names
Persistent Pupillary Membrane


Causes
Inheritance is not defined. For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.

Breeds Affected
PPM are known or strongly suspected to be inherited in the Basenji, Pembroke and Cardigan Welsh Corgi, Mastiff, and Chow Chow. This problem is particularly significant in the Basenji where the strands often bridge to the cornea, causing opacities which may impair sight. In the Basenji the condition has been seen with optic nerve coloboma - a cavity in the optic nerve which, if large, causes blindness.

PPM are also seen in many other breeds, including the Akita, Alaskan Malamute, American and English Cocker Spaniel, Australian Shepherd, Basset Griffin Vendeen (petite), Beagle, Bearded Collie, Belgian Sheepdog, Belgian Tervuren, Bichon Frise, Bouviers des Flandres, Chesapeake Bay Retriever, Collie (rough and smooth), Doberman Pinscher, English Springer Spaniel, Golden Retriever, Gordon Setter, Havenese, Irish Setter, Labrador Retriever, Lakeland Terrier, Lowchen, Miniature Bull Terrier, Norwegian Elkhound, Nova Scotia Duck Tolling Retriever, Old English Sheepdog, Papillon, Poodle (all sizes), Portuguese Water Dog, Samoyed, Scottish Terrier, Shetland Sheepdog, Soft-Coated Wheaten Terrier, Tibetan Terrier, Welsh Springer Spaniel, West Highland White Terrier, Yorkshire Terrier.


Symptoms
Generally persistent pupillary membranes cause no problems. However if attached to the cornea or lens, the strands can cause opacities which may interfere with vision. The cataracts that can occur with PPM usually don't worsen.

Diagnosis
PPM are seen in young dogs. You or your veterinarian may notice small white spots in your dog's eyes, or you may suspect that your dog's vision is impaired if the condition is severe. With an ophthalmoscope, your veterinarian will be able to see the membranous strands, and whether they adhere to the lens or cornea.

Treatment
There is generally no treatment for persistent pupillary membrane, but in most cases, there is no real problem either. Only in the most problematic of cases will vision be significantly impaired, and if cataracts develop, they are treated with surgery, the same as they would be in any other animal, usually to great success.

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