Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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January 31, 2019
Morning glory disc anomaly (MGDA) with associated abnormalities
- Background
- Morning glory disc anomaly (MGDA) is a congenital optic nerve anomaly characterized by a funnel-shaped excavation of the posterior globe that incorporates the optic disc.
- MGDA has been reported to be associated with numerous ocular abnormalities including retinal detachment, persistent hyperplastic primary vitreous, congenital cataract, nanophthalmos, eyelid hemangioma, drusen, and preretinal gliosis.
- Abnormalities of the visual pathways have also been reported in MGDA, including atrophy/hypoplasia of the contralateral optic chiasm as well as optic nerve glioma.
- Mutations in the PAX6 gene detected in our patient help to further emphasize the genetic interpretation of various manifestations of optic nerve malformations, including MGDA, as well as cataracts, as the PAX6 protein controls many aspects of eye development before birth.
- Clinical Presentation
- Clinically, infants with MGDA often manifest with strabismus or leukokoria (white pupillary defect). Due to unilateral involvement in most cases, an afferent pupillary defect can be noted.
- Key Diagnostic Features
- Funnel-shaped morphologic pattern of the posterior right optic disc with elevation of the adjacent retinal surface.
- Abnormal tissue associated with the distal intraorbital segment of the right optic nerve, with effacement of the regional subarachnoid spaces.
- Discontinuity of the uveoscleral coat
- Differential Diagnosis
- Optic nerve coloboma: No central glial tuft and there is minimal peripapillary pigmentary disturbance.
- Optic pits and peripapillary contractile staphyloma: Lack of central glial tuft and normal retinal vasculature.
- Treatment
- The visual prognosis in MGDA is poor. In addition to the abnormal disc itself and the predilection for retinal detachment, there is an added compounding variable of high refractive errors, amblyopia, and strabismus. Although ocular realignment surgery and treatment of anisometropic amblyopia is recommended and may result in some recuperation of vision, it is rare to see dramatic improvements.
- Treatment of the other associated abnormalities requires an interdisciplinary approach, often including neurosurgery, interventional neuroradiology, otolaryngology, and dentistry.
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