Retinal Diseases of the Eye and other types of Blindness

Some signs that your dog may be experiencing vision loss or blindness include general clumsiness, bumping into walls and furniture, startling easily and apprehensive behavior, inability to find toys or food and water bowls, reluctance to go out at night, excessive sleeping or loss of playfulness, disorientation or

The causes of vision loss and blindness in dogs range from normal aging and heredity to disease and injury. Vision problems ranging from hazy vision to complete blindness occur in many dogs as part of the aging process. An untreated eye infection or stroke may result in temporary or permanent blindness. Blindness is sometimes a secondary symptom to other canine diseases such as heart, liver, and kidney ailments or systemic diseases such as diabetes.

Some signs that your dog may be experiencing vision loss or blindness include general clumsiness, bumping into walls and furniture, startling easily and apprehensive behavior, inability to find toys or food and water bowls, reluctance to go out at night, excessive sleeping or loss of playfulness, disorientation or confusion, or changes in the appearance of the eyes. If you notice these behaviors in your dog, you should seek immediate veterinary care.

Your veterinarian will likely conduct a thorough physical exam to determine the cause and extent of the dog’s vision loss. This may include blood work, neurological exam, cerebral spinal fluid test, MCR or CT scan, and ophthalmologic exam. You may be referred to a veterinary ophthalmology specialist. Treatment of the condition will depend on the cause. And while the vision loss may not be reversible, your dog can still live a fulfilling life after adjusting to his new condition.

Cataracts

Cataracts, a condition where the normally transparent lens turns cloudy preventing light from reaching the retina, can result in partial or total blindness. It can be inherited or caused by infections, injury, and other diseases as well as diabetes. Cataracts can develop very quickly. Early intervention through surgery may save a dog’s sight. However, if caused by diabetes, healing may be slowed and scarring could result in less than optimal results. If left untreated, cataracts can sometimes cause an inflammation called Lens-Induced Uveitis (LIU) causing glaucoma. And if the LIU is untreated and glaucoma develops, cataract surgery might not be possible.

Macular Degeneration

 Age-related macular degeneration (AMD) is a retinal degenerative disease that causes a progressive loss of central vision. Macular degeneration destroys the part of your eye that enables you to see details.

Retinitis Pigmentosa

 Retinitis pigmentosa (RP) is a group of genetic eye conditions. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades.

Day Blindness

The cones in your dog’s eyes can degenerate as a result of a mutant gene known as CNGB3. This condition is also known as hemeralopia. It is usually around your puppy’s seven-week age that the first signs of this condition will appear. The bright light of day renders your pet almost blind, and they are fearful to venture into brightly lit areas. This was first detected in the mid 1960’s. Research with test breeding found that both parents must carry the gene (autosomal recessive disease) to affect the offspring. Day blindness comes from deteriorating ‘cones’ in the retina of your dog’s eyes. The cones enable your pet to see in the bright daylight.  Degeneration of these cones affects the day sight.  Exposure of your young pup to daylight causes irritation or pain. At night, they recover their eyesight and can move freely. There is no cure yet, although ongoing research is continuing. It means that support and management and helping your dog to get familiar with his back yard will help him to become a regular dog. The use of canine sunglasses or goggles with dark lenses may be helpful. These glasses are more than just a fun accessory; the army has utilized these for field dogs to protect their eyes from dust or dryness when skydiving with their people. The tinted glass may just help your dog enough for him to become more mobile during the day. 

PRA

Progressive Retinal Atrophy (PRA) is an inherited condition where the cells of the retina deteriorate causing blindness. Although not painful, both eyes are affected. It is found most often in Collies, Poodles, Schnauzers and Cocker Spaniels. The first sign of PRA is decreased night vision. Your dog may become more reluctant to go out after dark or become disoriented in low light situations. This is a degenerative disease with no cure. However, there are some antioxidant supplements available to slow the deterioration of your dog's sight. Progressive Retinal Atrophy (PRA) is fairly common in dogs and affects the retina causing loss of sight. The rod shape cone cells in your dog’s eyes are not affected with this condition, and all sight is lost.

SARDS

A more tragic and scary condition is Suddenly Acquired Retinal Degeneration Syndrome (SARDS). Similar to PRA, it involves the deterioration of the retina, usually affects both eyes, and causes no pain. Unlike PRA, the blindness is sudden rather than gradual, with total blindness occurring over a few days to several weeks. Older dogs, females, and overweight dogs appear to be more at risk. The disease is diagnosed by a lack of electrical activity within the retina. Initial observation of the eye shows no structural damage, but the retina degenerates quickly. University of Iowa College of Veterinary Medicine has had some success in restoring the sight of dogs, but treatments are still experimental. The long-term prognosis is still unknown and the costs are high. 

Glaucoma

Is actually four different eye conditions that can damage your optic nerve, which carries visual information from your eyes to the brain. Glaucoma a painful condition where fluid pressure increases inside the eye causing damage to the retina and optic nerves resulting in partial or total blindness. The pain is similar to that of a migraine headache. Symptoms include dilation of one or both pupils, green or yellow discharge from the eye(s), delayed response to bright light, or bloodshot eyes. Seek veterinary care as soon as possible if you notice any of these symptoms. Both medical and surgical treatments are available, but are more successful with early intervention.