Pronunciation Key: blef-ar-o-spazim
The correct answer to the introduction question is: none of the above, as this condition is a rapid blinking of the eye due to involuntary contractions of the orbicularis oculi muscle of the eyelid.1 This is a quick type of spasm, sometimes appearing as if the eyelid is closed. The pet may also show tearing or other discharge from the eye, and be reluctant to look at bright lights in addition to the blepharospasm.
Blepharospasm is not a disease in and of itself; it is a clinical sign that something is wrong with the eye or eyelid in most cases. Some cases may involve only the fifth cranial nerve (Trigeminal nerve) or neither the eye or the Trigeminal nerve (essential blepharospasm)2
In most cases of blepharospasm seen in dogs and cats, the eye has been injured or infected. The eye is most often painful.
Special note:
Diseases of the eye can worsen quickly; it is important to see your veterinarian as soon as possible if you notice your pet squinting, showing tearing or other discharge, or experiencing blepharospasm of the eye(s).
References:
1 blepharospasm. (n.d.). Merriam-Webster's Medical Dictionary. Retrieved November 10, 2006, from Dictionary.com website: http://dictionary.reference.com/browse/blepharospasm
2 Dorland's Illustrated Medical Dictionary, Twenty-sixth Edition.
