Related Experiment Video
Updated: Aug 11, 2026

Intense Pulsed Light for the Treatment of Dry Eye Owing to Meibomian Gland Dysfunction
Published on: April 1, 2019
A novel mechanism for benign essential blepharospasm
J D McCann1, M Gauthier, R Morschbacher
1Division of Orbital and Ophthalmic Plastic Surgery, Jules Stein Eye Institute, University of California at Los Angeles, 90095-7006, USA.
Purpose:
The purpose of this study is to test the hypothesis that the photophobia of benign essential blepharospasm (BEB) is caused by sympathetically maintained pain.
Methods:
Nineteen patients with photophobia and BEB were enrolled in an unblinded prospective treatment trial. The intervention was blockade of the superior sympathetic ganglion with local anesthetic. Outcome measures included the patient's subjective report of ocular surface dryness, foreign body sensation, and eyelid spasm. We also obtained video recordings of eyelid movements.
Results:
Of the 19 patients, 13 reported subjective improvement in BEB symptoms after cervical sympathetic blockade (CSB). Thirteen of 19 patients also had objective evidence of decreased light-induced eyelid spasm after CSB. Ocular surface disease was present in 18 of 19 patients.
Conclusion:
These data support the hypothesis that in many patients with BEB there is a sympathetically maintained pain syndrome associated with external ocular disease. We speculate on a neurologic circuit that may explain these findings.
Related Concept Videos
Cell Motility through Blebbing
Blebbing Through the Matrix
In multicellular...
Mechanism of Ciliary Motion
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
Direct-Acting Cholinergic Agonists: Therapeutic Uses
Open Angle Glaucoma: Treatment
Drugs such as carbonic anhydrase inhibitors, α2- and...
Muscles of the Eye
Extraocular Muscles
The six extraocular muscles surround the eyeball and control its movements. They are responsible for a wide range of eye motions, including looking up, down, left, right, and rotating...
Accessory Structures of the Eye

