Persistent Pupillary Membranes (PPM) is a low-severity eye condition that can affect dogs of all ages and breeds. PPMs are remnants of foetal blood vessels crossing the pupil that fail to fully regress after birth. Depending on what they attach to, they can cause iris-to-iris strands (benign), iris-to-lens adhesions (cataracts), or iris-to-cornea adhesions (corneal opacities). It is documented across 5 breeds, though prevalence and severity can differ significantly between them. It typically becomes apparent at Birth. Early signs to watch for include visible strands across pupil, corneal opacity if corneal attachment, lens opacity if lens attachment, and reduced vision in severe cases. When treatment is required, costs are estimated at £0-£1,500 depending on severity, location, and the specific intervention needed. Persistent Pupillary Membranes (PPM) has a hereditary component, so health-screening certificates from the breeder are strongly recommended for predisposed breeds. This page covers symptoms, treatment options, and preventive steps — along with breed-specific information where available.

Signs & Symptoms

The following symptoms are commonly associated with Persistent Pupillary Membranes (PPM) in dogs. If your dog displays several of these signs, consult your vet promptly — early diagnosis typically leads to better outcomes.

• Visible strands across pupil
• Corneal opacity if corneal attachment
• Lens opacity if lens attachment
• Reduced vision in severe cases
• Usually incidental finding

Treatment Overview

Iris-to-iris strands require no treatment. Iris-to-cornea or iris-to-lens forms may require monitoring or surgical management if causing significant visual impairment.

Typical onset: Birth

Prevention & Screening

While not all cases of Persistent Pupillary Membranes (PPM) can be prevented, the following steps reduce risk or enable earlier intervention:

• BVA/KC/ISDS eye scheme examination
• Do not breed dogs with significant iris-to-cornea or iris-to-lens PPMs

Breeds Affected by Persistent Pupillary Membranes (PPM)

The following 4 breeds are documented as being susceptible to Persistent Pupillary Membranes (PPM). Click any breed to view breed-specific information about this condition, including prevalence and recommended screening.

• Basenji (small)
• Chow Chow (medium)
• Shetland Sheepdog (small)
• Mastiff (giant)