Dog Blindness
There are many eye disorders that affect our dogs, and we’ve listed some of the more common ones here.
We are not veterinarians, and are offering an overview only, not as a diagnostic tool. Please see your veterinarian if you suspect any of these or other eye disorders in your dog.
This website is not substitute for a veterinarian examination.
This website is not substitute for a veterinarian examination.
EYE DISEASE GLOSSARY
Cataracts affect the lens of the eye, causing a film to form. In early stages, it often affects sight very little, and is usually more treatable. As cataracts mature, they cause worsened vision. Often confused with cataracts is a condition called nuclear sclerosis. This is a hardening and greying of the lens in older dogs. This is not a cataract, and does not affect vision. Cataracts can be treated surgically, and often restore sight, especially in early stages. However, not all dogs regain sight from cataracts. If you suspect your dog has cataracts, please see your veterinarian.
Cataracts in Dogs - VCA Animal Hospital Cataracts in Dogs - Fetch WebMD
Glaucoma is an increased pressure in the eyes. Fluid within the eye builds up and does not drain properly. Glaucoma causes blindness by damaging the optic nerve and by decreasing blood flow to the retina. This increased pressure can cause pain Glaucoma can be treated by eyedrops or surgically. The type of surgery depends on whether the dog will be able to retain any vision. Unfortunately, often the dog is already blind in the affected eye by the time the glaucoma is detected. Often the other eye is at risk for developing glaucoma, so vets may prescribe eyedrops to delay this from happening.
Glaucoma is an increased pressure in the eyes. Fluid within the eye builds up and does not drain properly. Glaucoma causes blindness by damaging the optic nerve and by decreasing blood flow to the retina. This increased pressure can cause pain Glaucoma can be treated by eyedrops or surgically. The type of surgery depends on whether the dog will be able to retain any vision. Unfortunately, often the dog is already blind in the affected eye by the time the glaucoma is detected. Often the other eye is at risk for developing glaucoma, so vets may prescribe eyedrops to delay this from happening.
Glaucoma in Dogs - VCA Animal Hospital
Progressive Retinal Atrophy (PRA or PRD) is an inherited disease of the retina, which is a tissue that surrounds the inside of the eyeball and works much like film in a camera. Often the first symptom is their dog becoming “night blind”, or having difficulty seeing in low light. Over time, the pupils become dilated, and owners may notice a glow from the dog’s eyes. The rate of progression varies from dog to dog, but blindness does come eventually. However, PRA is painless.
Progressive Retinal Atrophy (PRA or PRD) is an inherited disease of the retina, which is a tissue that surrounds the inside of the eyeball and works much like film in a camera. Often the first symptom is their dog becoming “night blind”, or having difficulty seeing in low light. Over time, the pupils become dilated, and owners may notice a glow from the dog’s eyes. The rate of progression varies from dog to dog, but blindness does come eventually. However, PRA is painless.
Suddenly Acquired Retinal Degeneration (SARDS) is a disease of the retina that causes blindness quickly, within a matter of days to weeks. Owners of dogs who develop SARDS may report noticing an increase in thirst and urination and weight gain in their dog. SARDS may also be associated with Cushing’s disease, which is the production of excess hormones from the pituitary gland that can cause a host of symptoms in dogs. SARDS is not painful. Please look at these links to learn more about SARDS.
Helpful Tips for Dog Owners Research Article: SARDS diagnosis Report: Findings Examining the Role of the Immune System in SARDS
OTHER CAUSES
Diabetes in dogs doesn't mean they can't live healthy lives. Unfortunately, a common complication of diabetes in dogs is cataracts (cloudy lenses). In fact, 75% of dogs develop cataracts and blindness in both eyes within one year of being diagnosed with diabetes. The cataracts develop very quickly — sometimes overnight! If untreated, the cataracts cause intraocular inflammation called Lens-Induced Uveitis (LIU) that harms the eyes by causing glaucoma (increased intraocular pressure). If the LIU is uncontrolled and glaucoma develops, cataract surgery might not be possible. Glaucoma causes a chronic headache (similar to a migraine). Once it is apparent that cataracts are forming, it is important to have your pet examined by a veterinary ophthalmologist as soon as possible.
Corneal Ulcer is a break in the outer layer or epithelium of the cornea. Uncomplicated ulcers, although initially painful, should heal in 3 to 4 days with appropriate treatment. Those ulcers that persist longer than this period of time often prove to be complicated ulcers.
Corneal Dystrophy appears as gray-white, crystalline or metallic opacities in the center of the cornea or close to the periphery. These opacities may affect any layer of the cornea, the epithelium (outer layer), the stroma (the thick, middle layer), or the endothelium (the inner layer). The opacities are usually oval or round and are sometimes doughnut-shaped.
Retinal Dysplasia is a type of retinal malformation. The word “dysplasia” simply means “a defective development of an organ or structure”. Retinal dysplasia occurs when the 2 primitive layers of the retina do not form together properly. Mild dysplasia manifests as folds in the inner retinal layer. These are called “retinal folds”. In “geographic” retinal dysplasia there are larger areas of defective retinal development. In the severe form of dysplasia, the 2 retinal layers do not come together at all and retinal detachment occurs. Retinal dysplasia is not progressive. It is a congenital defect and animals are born with as severe a condition as they will ever get.
Dry Eye - also known as Kerato Conjunctivitis Sicca (KCS) - describes the changes in the eye which result from lack of tear production. To understand “dry eye” it is helpful to know how tears help keep the cornea healthy. The cornea is the optically clear portion of the eye that allows entry of light into the eye. Like all living tissue, the cornea requires a supply of oxygen and energy to remain healthy. Oxygen and nutrients are supplied to most tissues by the blood that moves through the area in blood vessels. The healthy cornea has no blood vessels, if it did it wouldn’t be clear, so the oxygen and nutrients are supplied through the three-layered tear film.
Cherry Eye is a prolapsed gland of the third eyelid is thought to be associated with a laxity of a small ligament which holds the gland in a normal position behind the third eyelid. The gland is a tear producing gland, and produces about 30% of the tears, while the main orbital lacrimal gland produces the rest. Dogs that have had the gland of the third eyelid surgically excised have a greater risk of development of a dry eye (KCS) than dogs with intact third eyelid glands. It is thought that should the main orbital lacrimal gland be damaged later in life that there is no “backup” for tear production. Dry eye is a serious eye condition that is difficult to treat, and requires lifelong treatment which may be costly. If the chance of the development of a dry eye can be lessened by tacking the gland back into a normal position so that it stays functional, then this is the most desirable way of handling “cherry eye”.
Lens Luxation happens when the lens either becomes loosened (subluxated) or completely detached (luxated). When the lens completely tears free of its zonular attachments and falls forward into the anterior chamber, we call this an anterior luxation. It is also possible for the lens to luxate posteriorly into the vitreous body. Since lens luxation may cause glaucoma, and since glaucoma may cause lens luxation it is important to determine which disease came first. When lens luxation occurs secondarily to glaucoma, it usually occurs late in the disease once the elevated pressure within the eye has caused the sclera to stretch, and the zonular ligaments to tear. This does not occur until long after vision has been lost. In such a case, attention must be given to resolving the pain with glaucoma.
Double Merle, Double Dapple, Double Harlequin, Lethal White (Preventable) is a distinctive color pattern for some breeds, such as Australian Shepherds, Dachshunds, Collies and Shelties, and the double merle genetic defect can be found in any dog with the merle or dapple coat. Double Merles are also called lethal whites (a term used to refer to the more politically correct double merle (MM) gene, or homozygous genetic defect). In other words, when two merle dogs are bred together, a genetic defect will be created in some of the litter, and this defect will cause them to be blind and/or deaf. The affected puppies in the litter will also be colored mostly or completely white.
Horner’s Syndrome is not uncommon and occurs in dogs, cats, horses and many other species. The symptoms generally include a sunken in eye (enophthalmia) with a small pupil (miosis), a droopy upper eyelid (ptosis) and a prominant third eyelid. Horner’s Syndrome must be differentiated from Uveitis which also produces a constricted pupil and a droopy looking eye.
Uveitis is a viral infection which can often occur in horses and humans, but rarely in dogs. Uveitis means “inflammation of the uvea”, or the middle layer of the eye. The uvea consists of three structures: the iris, the ciliary body, and the choroid. The iris is the colored structure surrounding the pupil, visible in the front of the eye. The ciliary body is a structure containing muscle and is located behind the iris which focuses the lens. The choroid is a layer containing blood vessels that line the back of the eye and is located between the inner visually sensitive layer, called the retina, and the outer white eye wall, called the sclera. Inflammation occurring in any of these three structures is termed “uveitis”.