Morning Glory Disc Anomaly

Morning glory disc anomaly (MGDA) is the result of abnormal development of the distal optic stalk at its junction with the primitive optic vesicle. The anomaly is typically unilateral and is more common in girls. Serous retinal detachments occur in one-third of cases. MGDA has been associated with basal encephalocele in patients with midline abnormalities, PHACE syndrome (posterior fossa malformations, hemangiomas, arterial lesions, cardiac and eye anomalies), and carotid circulation abnormalities (moyamoya disease).

Figure 26-2 Coronal T1-weighted magnetic resonance imaging (MRI) scan of the lateral ventricles: the septum pellucidum (interventricular septum) is absent.

(Courtesy of Jane L. Weissman, MD.)

Figure 26-3 Coronal T2-weighted MRI scan of the orbits: the right optic nerve is smaller and more T2 hyperintense than the left optic nerve.

(Courtesy of Jane L. Weissman, MD.)

MGDA typically appears as a funnel-shaped excavation of the posterior fundus that incorporates an enlarged optic disc with elevated surrounding retinal pigment epithelium and an increased number of blood vessels looping at the edges of the disc (Fig 26-4). A core of white glial tissue occupies the normal position of the optic cup. This tissue may have contractile elements, as the optic cup can sometimes be seen to open and close with some periodicity.

Visual acuity ranges from 20/20 to no light perception, but it is usually 20/100 to 20/200. Because of the potential for associated CNS abnormalities, MRI and MR angiography should be considered.

Figure 26-4 Morning glory disc anomaly, left eye.

Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.