Persistant Pupillary Membranes

PPM's may or may not be a problem in a breed and/or individual dogs. PPMs are remnants of a fetal structure called the pupillary membrane. This membrane covers the pupil before an animal is born. It is part of the blood supply to the developing lens (the structure in the eye that focuses light on the retina). Normally the pupillary membrane completely absorbs before birth in foals and calves but is partially present and continues to disappear in neonatal dogs. Absorption may not be complete in puppies when the eyes first open and small strands or a web-like structure may be seen across the pupil. These strands normally disappear by four to five weeks of age. In some dogs these strands do not disappear and become PPMs.

Persistent pupillary membranes

Persistent pupillary membranes (PPM's) are the remnants of a normal embryologic structure of the eye. During fetal development they are continuous with the blood supply of the developing lens. The pupillary membrane begins to atrophy during fetal life, but atrophy may not be complete until 4 to 8 weeks of age. These strands are considered to be "persistent" when they do not regress by 8 weeks of age.


Persistent pupillary membranes are strands of tissue in the eye. b> Persistent Pupillary Membranes (PPM's) Blind Dog and Canine Vision Resources

Anterior Uvea - The Merck Veterinary Manual

Persistent pupillary membranes are remnants of the normal prenatal vascular diseases and infectious diseases such as infectious canine hepatitis,

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Canine and Feline Uvea. Ellison Bentley, DVM, Diplomate. ACVO. University of WisconsinMadison Persistent pupillary membranes. Courtesy C Murphy

CERF NEWS February 2002

The discussions with the AKC were concerning the Canine Health Information b> persistent pupillary membranes, retinal dysplasia (folds and geographic

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Incomplete atrophy leaves remnants termed persistent pupillary membranes (PPMs). For a list of other web pages on Canine Eye Disorders visit: