Credit: National Eye Institute
Uveal coloboma refers to missing parts of the uveal tract—the middle layer of eye tissue that includes the iris, the ciliary body, and the blood vessel-rich choroid. Marked is the approximate location of the optic fissure, which normally closes during embryonic development. Failure of the fissure to close anywhere along this line results in a coloboma. A coloboma's impact on vision varies according to its location and severity. It can cause anything from slight blurriness to blindness.