Persistent Pupillary Membrane or PPMs are the remnants of a membrane
that covers the eye before the puppy is born. This pupillary membrane is
the blood supply of the lens before birth. This condition usually
causes no problems with the dog's vision.
There are different types of PPMs.
There may be a single strand of leftover membrane or many.
PPMs may be attached at both ends, crossing the field of vision or be
attached at only one end. The iris is the colored part of the eye, the pupil
is the black part.
IRIS to IRIS PPMs: when the PPM strand crosses over the pupil,
IRIS to LENS PPMs may cause cataracts if the PPM strand
touches the lens. These cataracts rarely cause problems.
This type of cataracts does not grow larger.
IRIS to CORNEA PPMs can cause the most problems, causing
opacitites in the cornea, and may cause fluid build up when the
inside of the cornea is irritated by the the PPM.
PPMs can be mild or severe, and a puppy that is blind, may have
improved vision when he grows older as the PPMs break apart.
In horses and cattle this membrane reabsorbs before birth,
but in dogs this continues to be reabsorbed until the puppies are
between four and five weeks old.
PPMs will be discovered when the CERF exam is done.
No treatment is recommended for this condition.
Many breeds have PPMs that do not affect vision,
but CERF will not certify the following breeds:
Basenjis, Chow Chow, Yorkshire Terriers, Mastiff,Pembroke Welsh Corgi
if they have PPMs because they have been known to produce puppies with
PPMs that do cause blindness. This is believed to be hereditary and is
discouraged in these breeds.
Breeders of other breeds affected with PPMs are encouraged to be careful
breeding their dogs, since this has been found to be hereditary in other
breeds. The recommendation is to breed a dog with PPMs to a
dog that does not have PPMs. Over time, the incidence of
PPMs will be reduced in the bloodline.
that covers the eye before the puppy is born. This pupillary membrane is
the blood supply of the lens before birth. This condition usually
causes no problems with the dog's vision.
There are different types of PPMs.
There may be a single strand of leftover membrane or many.
PPMs may be attached at both ends, crossing the field of vision or be
attached at only one end. The iris is the colored part of the eye, the pupil
is the black part.
IRIS to IRIS PPMs: when the PPM strand crosses over the pupil,
IRIS to LENS PPMs may cause cataracts if the PPM strand
touches the lens. These cataracts rarely cause problems.
This type of cataracts does not grow larger.
IRIS to CORNEA PPMs can cause the most problems, causing
opacitites in the cornea, and may cause fluid build up when the
inside of the cornea is irritated by the the PPM.
PPMs can be mild or severe, and a puppy that is blind, may have
improved vision when he grows older as the PPMs break apart.
In horses and cattle this membrane reabsorbs before birth,
but in dogs this continues to be reabsorbed until the puppies are
between four and five weeks old.
PPMs will be discovered when the CERF exam is done.
No treatment is recommended for this condition.
Many breeds have PPMs that do not affect vision,
but CERF will not certify the following breeds:
Basenjis, Chow Chow, Yorkshire Terriers, Mastiff,Pembroke Welsh Corgi
if they have PPMs because they have been known to produce puppies with
PPMs that do cause blindness. This is believed to be hereditary and is
discouraged in these breeds.
Breeders of other breeds affected with PPMs are encouraged to be careful
breeding their dogs, since this has been found to be hereditary in other
breeds. The recommendation is to breed a dog with PPMs to a
dog that does not have PPMs. Over time, the incidence of
PPMs will be reduced in the bloodline.
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