Optic Disk Coloboma (Morning Glory Disk)

Disorders in which the Margin of the Optic Disk is Well Defined

Optic Disk Coloboma (Morning Glory Disk)

An optic disk coloboma (Fig. 13.18) is the result of incomplete closure of the embryonic optic cup. The optic disk is enlarged with a funnel-shaped depres-sion with whitish tissue and a peripapillary pigment ring. The retinal vessels extend outward across the margin of the disk in a radial pattern without a central trunk vessel. Patients with optic disk coloboma often have decreasedvisual acuity and visual field defects.