What is your diagnosis?
A 68-year-old man with diabetes and hypertension presents with loss of vision in the right eye on awakening.
The diagnosis is...
The image is consistent with a diagnosis of nonarteritic anterior ischemic optic neuropathy:
- Anterior ischemic optic neuropathy (AION) is a loss of vision due to interrupted blood flow to the optic nerve head.
- It is a common cause of permanent vision loss in patients older than 50, and it is characterized by a sudden, painless decline of vision—either unilateral or bilateral—typically noticed upon waking.
- AION is characterized as arteritic or nonarteritic:
- Arteritic AION is caused by inflammation and thrombosis of the posterior ciliary arteries due to giant cell arteritis. Patients often present with symptoms of underlying disease, amaurosis fugax, and early massive vision loss.
- Nonarteritic AION is caused by either transient nonperfusion or hypoperfusion of the optic nerve head or embolic lesions of the vessels supplying the optic nerve head. Risk factors include hypertension, diabetes, hyperlipidemia, atherosclerosis, raised intraocular pressure, and optic disc abnormalities.
What is the role of the primary care or emergency medicine physician?
- Refer to ophthalmology urgently to prevent further permanent visual loss in 1 or both eyes.
- Work up the patient for underlying etiologies (eg, giant cell arteritis, diabetes, hypertension, cardiac disease, sleep apnea) as indicated.
What is the role of the ophthalmologist?
- Assess visual acuity, visual fields, and extraocular motility (eg, diplopia).
- Perform a fundoscopic exam to assess for optic disc edema. Arteritic AION presents with chalky white optic disc edema and cupping.
- Differentiate between ischemic and nonischemic optic neuropathy using fundus fluorescein angiography.
- Work up the patient for underlying etiologies as indicated.
What is the treatment?
Patients with nonarteritic AION should be treated for underlying cardiovascular disease and/or aggravating risk factors. In select cases, corticosteroid therapy may also be considered in the acute setting.
Arteritic AION is managed with systemic corticosteroid therapy, starting with emergency high-dose intravenous steroids for 2-3 weeks, followed by a taper and lifelong low-dose regimen. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) should be monitored to guide steroid taper. Follow-up with a rheumatologist is recommended to consider a steroid-sparing agent.
Learn more: Ophthalmology resources for medical students