Incipient Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) Evolving to Symptomatic NAION

A 54-year old woman with hypertension was seen in neuro-ophthalmology consultation for asymptomatic left optic disc edema. She had a small, crowded optic disc in the right eye known as a "disc-at-risk" (Figure 1). Her visual function including 24-2 SITA-Fast Humphrey visual fields were normal in both eyes (Figure 2). MRI of the brain and orbits with contrast was normal without any signs of an optic nerve sheath meningioma or chronically raised intracranial pressure (Figure 3). One month later she lost vision in the upper part of her visual field in the left eye and her examination revealed more prominent left inferior optic disc edema with a new optic disc hemorrhage (Figure 4). Intravenous fluorescein angiography of the optic disc showed leakage, confirming the optic disc edema (Figure 5). Humphrey 24-2 SITA-Fast visual fields showed a new left altitudinal defect corresponding to the increase in inferior optic disc edema (Figure 6). One month later she lost vision in the inferior part of the visual field in her left eye and there was an increase in the optic disc edema in the superior part of the left optic nerve (Figures 7 and 8). Humphrey 24-2 visual fields showed generalized depression in the left eye (Figure 9). She was seen in follow-up 6 weeks later and the left optic disc edema resolved and there was diffuse pallor (Figures 10 and 12). She had a mild improvement in her visual fields at that time (Figure 11). [[Figure 1. Optic disc photos of both eyes demonstrating left optic disc edema and a right small, crowded optic nerve ("disc-at-risk"). Figure 2. Normal 24-2 SITA-Fast Humphrey visual fields. Figure 3. Normal MRI of the orbits with contrast. There were no signs of an optic nerve sheath meningioma or intracranial hypertension. Figure 4. Optic disc photos show an increase in the inferior optic disc edema with a new optic disc hemorrhage. Figure 5. Intravenous fluorescein angiography shows leakage of the optic disc, confirming optic disc edema. Figure 6. Humphrey 24-2 SITA-Fast visual fields show a superior altitudinal defect in the left eye. Figure 7. Optic disc photos show an improvement of the inferior optic disc edema and an increase in superior optic disc edema. Figure 8. Compared to her previous optic disc photos, there is an improvement in the inferior optic disc edema and an increase in the superior optic disc edema. Figure 9. Humphrey 24-2 SITA-Fast visual fields show generalized depression in the left eye. Figure 10. Optic disc photos show diffuse pallor in the left eye. Figure 11. Humphrey 24-2 SITA-Fast visual fields are improved compared to the previous visit. Figure 12. Optic disc photos and 24-2 SITA-Fast visual fields show the evolution of the optic disc edema and visual function over time.]]