Common Causes of Canine Vision Loss

Canine vision loss can occur for several reasons and may occur gradually or suddenly, depending on the cause. Recognizing the symptoms of vision loss and catching the problem early may minimize or prevent blindness in your dog. Vision impaired dogs can go on to live full and active lives with the use of their other senses and some patience and training from owners.

Symptoms of Vision Loss

Signs that your dog could be losing sight in one or both eyes include:

  • Clumsiness
  • Hesitation before entering dark rooms or unfamiliar areas
  • Difficulty finding familiar objects like food and water bowls
  • Lethargy and excessive sleeping
  • Enlarged eyeball(s)
  • Change of pupil color
  • Startled or aggressive behavior, even around familiar faces
  • Scratching, pawing or rubbing of the eyes or head
  • Watery or inflamed eyes
  • Eye discharge or crusty eyes

Common Causes of Dog Vision Loss

Cataracts: Cataracts cause clouding of the eye lens and vision loss and is usually an inherited condition, though symptoms can develop as a result of eye trauma, diabetes or poor nutrition. Surgery is a common and successful treatment option but can't be used in all cases.

Glaucoma: This painful disease is caused by the buildup of fluids in the eye, resulting in increased pressure. Glaucoma must be recognized immediately in order to prevent vision loss. Owners should look for signs of redness, swelling, squinting, rubbing and watery eyes. Glaucoma can also develop as a result of cataract surgery, injury to the eye, tumors or medication.

Dry eye syndrome: Dry eye is caused when the tear film of the eye is damaged due to medication, infections like canine distemper or a congenital defect. Cocker Spaniels, Bulldogs, Shih Tzus and Lhasa Apsos often develop dry eye as a result of an autoimmune disease that attacks the tear glands.

In-grown eyelids/Entropion: Entropion is a condition that causes the eyelids to roll inwards, often irritating the cornea. This problem can develop due to genetics or repeated inflammation of the eye that is left untreated.

Corneal ulcers: These ulcers are a common problem in both dogs and cats and can cause vision loss. A scratched cornea due to a foreign object, scratch from another animal or sharp object and cause an ulcer to develop. If this ulcer becomes infected and is left untreated a corneal ulcer can cause blindness.

Progressive Retinol Atrophy (PRA): PRA covers a group of degenerative genetic diseases affecting the retina that cause gradual vision loss. There is no treatment to stop Progressive Retinol Atrophy. Cocker Spaniels, Labradors and Poodles often inherit this disease so breeders should use blood tests to determine if their dogs are carriers.

Preventing Vision Loss in Your Dog

CERF, or Canine Eye Registration Foundation, maintains a database to monitor inherited eye disease in purebred dogs. The CERF certification is only valid for one year so annual check-ups are essential to prevent genetic diseases from being passed on through breeding.

Vision loss can occur at any age and owners must look for symptoms of eye problems as part of a general health examination routine. Even small scratches to a puppy's eye can result in glaucoma or corneal ulcers so a trip the vet is essential for early treatment and vision loss prevention.