How many types of Coloboma are there?

There are different kinds of coloboma, depending on which part of the eye is missing. Coloboma can affect the: eyelid lens macula optic nerve uvea Eyelid Coloboma In eyelid coloboma a piece of either the upper or lower eyelid is absent. Eyelid coloboma may be part of a genetic syndrome, or happen as a result of a disruption of eyelid development in a baby. A syndrome is a specific grouping of birth defects or symptoms present in one person. Lens Coloboma In this type of coloboma, a piece of the lens is absent. The lens, which helps focus light on the retina, will typically appear with a notch. Macular Coloboma This happens when the center of the retina, called the macula, does not develop normally. The macula is responsible for daylight, fine and color vision. Macular coloboma may be caused when normal eye development is interrupted or following an inflammation of the retina during development of the baby.   Optic Nerve Coloboma Optic nerve coloboma refers to one of two distinct things: 1. An abnormal optic nerve that is deeply "excavated" or hollowed out. In some cases it can also be referred to as an optic nerve pit. The optic nerve is the bundle of nerve fibers that relays the light signals from the eye to the brain. 2. A uveal coloboma that is large enough to involve the optic nerve, either the inferior portion or the entire optic disc.   Read more articles on Coloboma