Optic Neuropathy Mimicking Normal Tension Glaucoma Associated with Internal Carotid Artery Hypoplasia

Abstract

Enlargement (excavation) of the right optic disc was discovered in a 41-year-old woman during an examination to fit her for contact lenses. She was initially diagnosed with normal tension glaucoma (NTG) in that eye and subsequently treated with topical medication. However, Goldmann perimetry results indicated there were changes in the temporal visual field that were not typical for glaucoma. In addition, magnetic resonance angiography (MRA), three-dimensional computed tomographic angiography (3D-CT) and orbital color Doppler imaging (CDI) results revealed the presence of segmental hypoplasia and stenosis of the right cervical internal carotid artery (ICA). The patient therefore had ipsilateral coexisting ICA hypoplasia and optic neuropathy. We postulate that the visual field change in this patient was due to an ischaemic event in the optic nerve that was related to a congenital anomaly of the right cervical ICA.

Keywords:

• Optic neuropathy
• normal tension glaucoma
• internal carotid artery (ICA)