Health Issue – Eyes
To minimize the risk of passing on congenital eye abnormalities in their offspring, the Samoyed Club of America advises that all breeding animals be:
- evaluated by a veterinary ophthalmologist annually
- undergo the genetic screen for X-Linked Progressive Retinal Atrophy
- undergo the genetic screen for Retinal Dysplasia/OSD
Samoyeds may develop a variety of different types of cataracts, including juvenile cataracts and anterior or posterior punctate cataracts. Poor nutrition can also cause cataracts. Many advanced-age Samoyeds will develop age-related cataracts, as do their human companions. Some types of cataracts are inherited, which is why the Samoyed Club of America recommends annual eye examinations for all dogs used for breeding. Symptoms of cataracts are cloudiness in the pupil of the eye, inflammation around the eye and squinting. Some cataracts can only be detected when a veterinary ophthalmologist examines the eye. Treatment will range widely based on the type & severity of cataract, from no treatment for minor punctate cataracts to surgery for advanced cataracts that can lead to blindness.
Glaucoma has been reported in the Samoyed (Clark, 2014), but has not been seen by the American College of Veterinary Ophthalmologists in the over 4,900 dogs undergoing screening exams between 2010 and 2014 (ACVO, 2015). Glaucoma is a condition impacting one or both eyes where the pressure within the globe of the eye increases, resulting in damage to the optic nerve and retina. This most frequently occurs when the drainage system of the eye is blocked. This condition may lead to blindness, but the prognosis can be improved with early diagnosis and treatment. Symptoms include excessive tearing, redness, squinting and sensitivity to light. A veterinary ophthalmologist measures the pressure within the eye to diagnose the condition. Treatment is based on the severity of the presentation and may range from eye drops to surgery to remove the affected globe.
Distichiasis has been reported in 5.8% of the over 22,500 Samoyeds examined by American College of Veterinary Ophthalmologists (2015) in the years between 1991 and 2014. Distichiasis is a disorder where eyelashes emerge from the ducts within the eyelid that do not normally produce hairs. These hairs may not cause any problems or cause irritation to the cornea of the eye. Symptoms of problematic distichiasis include redness, squinting, excessive tearing, tear staining of the eye, and rubbing the eyes. Treatment, if required, will vary depending on how many extra eyelashes there are and their location.
Persistent Pupillary Membrane
Persistent pupillary membrane (PPM), seen in less than 4% of Samoyeds examined (AVCO, 2015), is a disorder where blood vessels that exist in the fetal puppy’s eye fail to go away by 3 months of age. These vessels may arise from the thickest portion of the iris and may bridge from iris to iris, iris to lens, iris to cornea or form sheets of tissue in the fluid-filled space between iris and cornea. Symptoms include problems with vision and vary based on the severity of the disorder. Treatment, if necessary, is surgery. It is important that a veterinary ophthalmologist evaluate puppies for this disorder before they are placed in their homes.
Progressive Retinal Atrophy
Progressive Retinal Atrophy (PRA) describes a number of diseases where the retina of the eye is destroyed over time, eventually resulting in blindness. It is seen in 1 – 2 % of the Samoyeds examined, (AVCO, 2015). The form of the disease most commonly seen in Samoyeds is X-linked PRA, where the mutant gene is only carried on the “X” sex chromosome. Fortunately, there is a genetic screening test that can be performed on breeding animals to assure this form of the disorder is not transmitted to the puppies. Of the Samoyeds screened for this form of PRA, 1% of the dogs are affected and 2% are carriers of the gene. (Bell, et al., 2012, p. 406). This is one of the conditions where it is important to assure the parents of a puppy have been tested and proven clear.
Initial symptoms include night blindness, where a dog will exhibit hesitancy to walk down dark stairways or into a dark hallway. It will progress to further loss of vision and eventual blindness. There is no treatment for Progressive Retinal Atrophy.
Retinal dysplasia is a term used to describe abnormal development of the retina. It is present at birth: therefore, it is important that a veterinary ophthalmologist evaluate puppies for this disorder before being placed in their homes and the parents both be screened with an AVCO eye exam and RD/OSD genetic screen offered by Optigen.
The condition is recognized in 3 forms: folds, geographic, detached.
Folds: Are seen by a veterinary ophthalmologist as faint lines of retinal folding. The folds may be single or multiple. In puppies, retinal folds can be seen as a transient phenomenon, resolving as the eye matures. Folds do not affect vision (Clark, 2014).
Geographic: Is seen as an irregularly shaped area of retinal development containing both areas of thinning and areas of elevation in the retina. This form may be associated with visual impairment.
Detached: Severe abnormal retinal development associated with separation of the retina from the back of the eye. This form results in visual impairment
Retinal dysplasia & OculoSkeletal Dysplasia (OSD)
There is one form of retinal dysplasia in the Samoyed that is an inherited defect affecting forelimb and eye development.
Affected dogs are of small stature with bowed forelegs and have eye abnormalities including cataracts, retinal folds, retinal dysplasia and detachment of the retina.
There is a genetic screening test that can be performed on breeding Samoyeds that assures their offspring will not have this form of retinal dysplasia. (American College of Veterinary Ophthalmologists, 2013, Samoyed p. 4) Of the 405 genetic screening tests submitted to the Orthopedic Foundation for Animals through 2014, no animals were affected and 0.25% were evaluated as being carriers. (OFA, 2015, p. 1).
Symptoms of retinal dysplasia include visual problems in the dog, which may be detected by the animal bumping into objects, being less active or appearing shy or withdrawn. There is no treatment for retinal dysplasia.