Sunday, September 12, 2010

Hyaloid Artery

The hyaloid artery is the terminal branch of the ophthalmic artery, which, in turn, is a branch of the internal carotid artery. It is contained within the optic stalk of the eye and extends from the optic disc through the vitreous humor to the lens. Usually fully regressed before birth, its purpose is to supply nutrient to the developing lens in the growing fetus.

The hyaloid artery usually regresses during the tenth week of the human embryological development as the lens grows independent of a blood supply. Its proximal portion remains as the central artery of the retina. Regression of the hyaloid artery leaves a clear central zone through the vitreous called the hyaloid canal or Cloquet's canal. Cloquet's canal is named after the man who first described it, French physician Jules Germain Cloquet (1790–1883).

Occasionally the artery may not fully regress, resulting in the condition persistent hyaloid artery. More commonly, small remnants of the artery may remain. Free remnants can sometimes be seen as "floaters". An anterior remnant of the hyaloid artery can be seen in some people as Mittendorf's dot, a small pinpoint-like scar on the posterior surface of the lens. A posterior remnant may be seen where the artery left the optic disc, and is known as Bergmeister's papilla.