Ocular Coloboma

Abstract

The fetal fissure closes in the inferonasal quadrant and may involve the iris, lens, retina, choroid, and optic nerve. Colobomas that involve the anterior segment of the eye may demonstrate a teardrop defect in the inferonasal quadrant of the iris. If the lens is also involved, the zonules in that quadrant may be loose or absent, producing a notch in the lens. Any or all layers of the posterior segment can be affected. Typically, chorioretinal colobomas have a white central defect outlined by pigment epithelium. There may be retina present within the defect, and it is not unusual to see some retinal vessels crossing through the defect. The clinical appearance of a disc coloboma may range from an enlarged and deep cup to a large hole with a retrobulbar cyst. In patients with retinal detachment, it is prudent to investigate for a break along the edge of the coloboma. Ideally, the optimal method for repairing these detachments involves a pars plana vitrectomy with endolaser photocoagulation and internal tamponade with gas or silicone oil.