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Here is a quick rundown of the most common forms of eye problems in dogs.
CEA (collie eye anomaly) is the most common form of eye problem found in the collie, both rough and smooth variety. It is also found in the border collie, shetland sheepdog, and bearded collie.
It is believed to by controlled by a genetic cluster, or large group of genes, and thus, it is hard to control by breeding, and ranges in severity.
PRA (progressive retinal atrophy) is common in many breeds of dogs (including mixed breeds), and is not isolated to the collie like the CEA tends to be.
PRA affects the entire retina and is the canine equivalent of retinitis pigmentosa. This disease manifests itself differently in different breeds. The most common form of PRA in the collie is detectable at early age (6 weeks and older). The form of PRA in Irish setters is also early-onset. In Labrador retrievers, on the other hand, the age of onset is much later, typically 4–6 years old, making it much harder to find and isolate carriers in this breed.
PRA has been detected as early as 6 weeks in puppies, and these puppies are usually blind by 6–8 months. An electroretinography can be used to detect the early signs of PRA.
Animals to be tested in this manner are anesthetized while lenses are placed on the eyes to record the retina’s reaction to light (like wearing contacts). In other cases, ophthalmological examination by ACVO-certified vets can pick up cases of PRA and confirm them with electroretinography if desired.
All dogs affected with PRA eventually go blind. Carriers show no clinical symptoms. Symptoms are subtle, starting with night blindness, some eye dilation, to progressive blindness. It’s quite common to not notice anything is wrong until the dog is nearly completely blind. Proactive testing is always recommended, especially for breeding stock.
This is a condition where the pressure of the fluid in the eye increases until the sight is gone in that eye.
If it strikes one eye, the other eye is likely also to be affected. Glaucoma is one of the leading causes of blindness in dogs. Any underlying problem that increases the fluid pressure inside the eye is the culprit. Most of the time this is due to inadequate drainage of fluid from the eye (as opposed to overproduction of fluid). A few forms of glaucoma are thought to be hereditary.
Signs of glaucoma include reddened conjunctival tissue (red eye), weeping, light sensitivity, or even enlargement of the eye. As pressure increases, the pupil can become dilated and the cornea cloudy. Early diagnosis is critical to save the vision of the dog, and involves treating the underlying causes of the increased pressure if at all possible.
There are several options in treatment, which depend on the extent to which the eye has been damaged, and the amount of vision that has been lost. In addition, some dogs will respond better than others to medications:
- Inject the eye with a fluid which kills the fluid producing cells in the eye, hence no further increase in pressure and no pain. This is not a guaranteed solution.
- Some glaucoma patients can be medically managed with anti-glaucoma drugs.
- Diode laser cyclophotoablation: This procedure uses the laser to burn holes in the ciliary body (the part of the eye that produces fluid). Fluid production is reduced/stopped and fluid pressure goes down quickly. This is treatment of choice if any vision is left to save. It’s not always permanent. Topical/oral drugs are still needed after surgery.
- Remove the eye and sew the lids shut. Probably the most practical.
- Remove the eye and replace it with a prosthetic (i.e., glass eye). There are potential problems with infection of the eye socket.
Cataracts are relatively common in dogs and most are hereditary. An ACVO-certified veterinarian can easily detect these cataracts. Haziness or cloudiness in the eyes in older animals is often not cataracts.
Hereditary cataracts can be found in many breeds of dogs and can be detected early in age, so all breeding stock should be screened for cataracts before being bred.
Cataracts may be stable or progressive. In the former case, owners may never be aware that their dog has cataracts until or unless the dog is examined. In the latter case, the dog often adapts very well to the gradual loss in vision until a certain point is reached. General diagnosis can be done by ophthalmoscopic examination; if a more detailed examination is needed, a slit lamp examination must be performed.
Surgery is the only option for cataracts that seriously impair vision. Most surgery involves removal of the lens; however, implants can also be performed. Recovery and prognosis for these dogs are generally good.
5. Retinal Dysplasia
There are several types of retinal dysplasia:
Relatively rare, puppies are blind from birth and appears to be a simple autosomal recessive. Mostly reported in Europe. No skeletal abnormalities are associated with this form of RD.
This form of RD is called “retinal and vitreal dysplasia with skeletal abnormalities” or “dwarfism with retinal dysplasia.” In this disease, 3 different ocular phenotypes are present — normal, localized retinal dysplasia (retinal folds), and complete retinal detachment — and 2 different skeletal phenotypes are present, normal or dwarf.
This is an inherited condition. Retinal folds may disappear with age, so an accurate evaluation for RD requires that puppies be evaluated, ideally between 8–10 weeks of age.
In mild cases of retinal dysplasia, sight is probably not affected much, if at all. In severe cases, skeletal abnormalities are present.
Dealing With Blindness
Dogs who become blind rarely have all that much trouble with it. Unlike humans, sight is not a primary sense. Dogs would be much more upset at losing their sense of smell.
Most people with a blind dog find that dealing with blindness is not difficult nor traumatic for the dog.
To avoid confusion, do not move your furniture around (except for any piece that the dog does keep bumping into). Be sure the dog knows when you are near so it is not startled. When you go out on walks, establish habitual trails. Your dog will adjust quickly.