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Disease of the Optic Nerve in Cats

 
Glaucoma is a condition in which high pressure occurs in the eye, with a failure of normal fluid drainage from the eye. A chronic condition with pressure against the optic nerve will eventually cause permanent damage to the optic nerve, resulting in blindness.

Symptoms and Types

There are two main types of glaucoma: primary and secondary. Symptoms for sudden primary disease, due to the eye's inability to drain through the filtration angles of the eye, are as follows:

• High pressure within the eye
• Blinking of the eye
• The eyeball may recede back into the head
• Redness of the blood vessels in the whites of eyes
• Cloudy appearance at front of the eye
• Dilated pupil – or pupil does not respond to light
• Vision loss

Long-term, advanced disease: 

• Enlargement of the eyeball (buphthalmos)
• Obvious loss of vision
• Advanced degeneration within the eye

Symptoms for secondary glaucoma, or glaucoma due to secondary eye infection(s), include: 

• High pressure within the eye
• Redness of the blood vessels in the whites of eyes
• Cloudy appearance at front of the eye
• Inflammatory debris visible in the front of the eye
• Possible constriction of the pupil
• Possible sticking of the iris to either the cornea or the lens
• Possible that the edge of the iris circularly sticks to the lens

In addition, there may be: 

• Headaches, with head pressing to relieve feelings of pressure in head
• Loss of appetite
• Change in attitude, less desire to play or interact

Causes

High pressure in the eye occurs when the normal outflow of fluid in the eye is impaired due to a primary eye disease such as the improper development of the eye's filtration angles, or secondary to other eye diseases such as primary lens luxation (slipping of the lens in the eye), inflammation of the tissues of the eye, eye tumor(s), or blood collection in the front of the eye from injury. In cats, secondary glaucoma is more common than primary glaucoma.