Notes and References. 1  U.S. Senate: Reference Home > Glossary > Christmas tree bill. 2  Lardner, George (1966) The Day Congress Played Santa: A Look at the Christmas Tree Bill, Washington Post, 25 December, p. A1, A10. 3  Shribman, David (1983) It Began as a Rather Ordinary Piece of Legislation, New York Times, 9 November, p. A22.
When the individual is awake, blinking of the eyelid causes rheum to be washed away with tears via the nasolacrimal duct. The absence of this action during sleep, however, results in a small amount of dry rheum accumulating in corners of the eye, most notably in children.
The most common known causes of eye twitch include fatigue, stress, anxiety, and excessive caffeine intake. Eyelid twitch may appear in response to irritation caused by smoke, dust, or a foreign body in the eye. Allergies and infections may also cause irritation that leads to twitching. Eyelid twitch is seen in primary congenital glaucoma.