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Sudden Onset Blindness in Cats

Posted July 21, 2014 in Cat Diseases & Conditions A-Z

Although sudden onset blindness occurs in cats, it’s likely that most cases are simply sudden awareness by the owners of a progressive loss of vision. Since pets lead generally sheltered lives and don’t rely on reading the fine print of life, gradual loss of vision may be so unapparent to owners that only once it progresses to total blindness do they become aware. I have seen a few cats that, when presented for annual physical examination, shocked their guardians by being blind in one eye. Cat's eye In fact, I have seen a few dogs and cats that were functionally blind but it had gone completely undetected. Much like with blind people, animals adapt well to their physical environment and once they are familiar with a room, they seem to navigate very well unless some item is moved.
Symptoms of sudden blindness

If blindness develops very rapidly, however, then there is no chance for the cat to adapt. The ASPCA lists signs of sudden blindness to include:

  • Disorientation
  • Confusion
  • Vocalization
  • Bumping into or falling from familiar objects adds that in many cases the pupils will be widely dilated and non responsive.

Causes of sudden blindness
Causes of blindness range from injury and tumors to infections and loss of function of a part of the eye such as the retina or lens. Many are unavoidable and many are progressive but your awareness and understanding of the disorder is important, if a treatment or management plan is needed.

  • Optic neuritis or inflammation of the optic nerve is relatively uncommon in cats but does occur and is associated with viral infections (feline infectious peritonitis), protozoal infections (toxoplasmosis), and fungal infections (cryptococcosis). The term “optic neuritis” compromises all diseases of the optic nerve that cause deterioration and usually produce a sudden visual field problem or total loss of vision in one or both eyes.
  • High blood pressure (hypertension) is frequently associated with a loss of vision and is one of the more common causes of retinal detachment, according to the Veterinary Vision, INC. website. The elevated blood pressure causes damage to the blood vessels in the retina resulting in bleeding or fluid seepage. This can further lead to separation or detachment of the retina resulting in blindness.
  • Retinal degeneration can also cause blindness and results in a loss of the light sensory cells in the retina. Though this is generally a slow and progressive
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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.