Ischemic optic neuropathy is infarction of the optic disc. It can be nonarteritic or arteritic. Both types cause painless acute vision loss. Diagnosis is based on findings from funduscopy and some blood testing. Treatment for the nonarteritic variety is ineffective. Treatment for the arteritic variety does not restore vision but can help protect an unaffected eye.
Two varieties of optic nerve infarction exist: nonarteritic and arteritic.
The nonarteritic variant occurs more frequently, typically affecting people approximately 50 years and older (1). Vision loss tends not to be as severe as in the arteritic variant, which usually affects an older age group, typically approximately 70 years and older (2).
Most ischemic optic neuropathy is unilateral. However, bilateral, sequential disease (progressing to involve the fellow eye) occurs in approximately 15% of patients with nonarteritic ischemic optic neuropathy within 5 years (3); bilateral simultaneous involvement is uncommon. Bilateral involvement is much more common among arteritic than nonarteritic cases.
Atherosclerotic narrowing of the posterior ciliary arteries may predispose to nonarteritic optic nerve infarction, particularly after a hypotensive episode. Any of the inflammatory arteritides, especially giant cell arteritis, can precipitate the arteritic form.
In this illustration, the top images show normal blood flow (left) and a normal optic nerve (right).
The bottom images show impaired blood flow (left) and a damaged optic nerve (right).
Alila Medical Media/stock.adobe.com
Acute ischemia causes nerve edema, which further worsens ischemia. A small optic cup to optic disc ratio is a risk factor for nonarteritic ischemic optic neuropathy but not for the arteritic variety. Usually, no medical condition is found as the apparent cause of the nonarteritic variety, although factors contributing to atherosclerosis (eg, diabetes, smoking, hypertension), obstructive sleep apnea, certain medications (eg, amiodarone, possibly phosphodiesterase-5 inhibitors and glucagon-like peptide-1 receptor agonists), and hypercoagulable disorders are present in some patients and are thought to be risk factors (, certain medications (eg, amiodarone, possibly phosphodiesterase-5 inhibitors and glucagon-like peptide-1 receptor agonists), and hypercoagulable disorders are present in some patients and are thought to be risk factors (1, 4). Vision loss on awakening leads investigators to suspect nocturnal hypotension as a potential cause of the nonarteritic variety.
General references
1. Biousse V, Newman NJ. Ischemic Optic Neuropathies. N Engl J Med. 2015;372(25):2428-2436. doi:10.1056/NEJMra1413352
2. Parreau S, Dentel A, Mhenni R, et al. Clinical, biological, and ophthalmological characteristics differentiating arteritic from non-arteritic anterior ischaemic optic neuropathy. Eye (Lond). 2023;37(10):2095-2100. doi:10.1038/s41433-022-02295-w
3. Newman NJ, Scherer R, Langenberg P, et al. The fellow eye in NAION: Report from the ischemic optic neuropathy decompression trial follow-up study. Am J Ophthalmol. 2022;134(3):317-328. doi: 10.1016/s0002-9394(02)01639-2
4. Fung KW, Baye F, Baik SH, et al. GLP-1 RAs and Risk of Nonarteritic Anterior Ischemic Optic Neuropathy in Older Patients With Diabetes. JAMA Ophthalmol. 2025;143(9):790-792. doi:10.1001/jamaophthalmol.2025.2299
Symptoms and Signs of Ischemic Optic Neuropathy
Vision loss with both varieties of optic nerve infarction is typically rapid (over minutes, hours, or days) and painless. Some patients notice the loss on awakening. In arteritic ischemic optic neuropathy due to giant cell arteritis, symptoms such as general malaise, muscle aches and pains, headaches over the temple, pain when combing hair, jaw claudication, and tenderness over the temporal artery are usually present; however, such symptoms may be absent in up to 20% of cases (1). Visual acuity is usually reduced, and an afferent pupillary defect (pupil dilatation rather than constriction when a light is swung from normal to affected eye) is present.
The optic disc is swollen and elevated, and the swollen nerve fibers obscure the fine surface vessels of the optic nerve. Often hemorrhages surround the optic disc. The optic disc may be pale in the arteritic variety because of occlusion of the posterior ciliary artery. The optic disc may appear hyperemic in the nonarteritic variety because of hypoperfusion causing edema and inflammation. In nonarteritic ischemic optic neuropathy, visual field examination often shows an altitudinal defect, while arteritic ischemic optic neuropathy typically causes more extensive visual field loss.
Symptoms and signs reference
1. Chen JJ, Leavitt JA, Fang C, et al. Evaluating the incidence of arteritic ischemic optic neuropathy and other causes of vision loss from giant cell arteritis. Ophthalmology. 2016;123(9):1999-2003. doi: 10.1016/j.ophtha.2016.05.008
Diagnosis of Ischemic Optic Neuropathy
Funduscopy
Erythrocyte sedimentation rate (ESR), C-reactive protein, and complete blood count (CBC)
CT or MRI of the brain and orbits if vision loss is progressive
Diagnosis of optic nerve infarction is based mainly on funduscopy, but ancillary testing may be needed. Most important is to exclude the arteritic variety because the other eye is at risk if glucocorticoid treatment is not started quickly. Immediate tests include ESR, CBC, and C-reactive protein. ESR is usually elevated in the arteritic variety, often exceeding 100 mm/hour, and normal in the nonarteritic variety. C-reactive protein is also elevated and is more sensitive than ESR in diagnosing giant cell arteritis (GCA). Only 3% of biopsy proven GCA have normal values for both C-reactive protein and ESR. CBC is performed to identify thrombocytosis (> 400 × 103/mcL), which adds to the positive and negative predictive value of using ESR alone (1, 2).
If giant cell arteritis is suspected, temporal artery biopsy should be performed as soon as feasible (at least within 1 to 2 weeks because effects of the prednisone therapy may reduce the diagnostic yield of histopathology). Changes in C-reactive protein level are useful for monitoring disease activity and the response to treatment. For cases of progressive vision loss, CT or MRI of the brain and orbits should be performed to exclude compressive lesions.If giant cell arteritis is suspected, temporal artery biopsy should be performed as soon as feasible (at least within 1 to 2 weeks because effects of the prednisone therapy may reduce the diagnostic yield of histopathology). Changes in C-reactive protein level are useful for monitoring disease activity and the response to treatment. For cases of progressive vision loss, CT or MRI of the brain and orbits should be performed to exclude compressive lesions.
For nonarteritic ischemic optic neuropathy, additional testing may be indicated based on the suspected cause or risk factor. For example, if patients have excessive daytime sleepiness or snoring or have obesity, polysomnography should be considered to diagnose obstructive sleep apnea.
Diagnosis references
1. Walvick MD, Walvick MP. Giant cell arteritis: Laboratory predictors of a positive temporal artery biopsy. Ophthalmology. 2011;118(6):1201-1204. doi:10.1016/j.ophtha.2010.10.002
2. Castillejo Becerra CM, Crowson CS, Langenfeld HE, et al. Population-Based Performance of Inflammatory Markers in Giant Cell Arteritis. Am J Ophthalmol. 2025;275:47-51. doi:10.1016/j.ajo.2025.03.022
Treatment of Ischemic Optic Neuropathy
Glucocorticoids and tocilizumab for the arteritic varietyGlucocorticoids and tocilizumab for the arteritic variety
The arteritic variety is treated with oral glucocorticoids (prednisone 80 mg orally once a day and tapered based on erythrocyte sedimentation rate and C-reactive protein) to protect the other eye. If there is vision loss, high dose intravenous glucocorticoids should be considered. Treatment should not be delayed while awaiting the biopsy procedure or its results. Results from clinical trials show that tocilizumab given when tapering glucocorticoids improves glucocorticoid-free remission when compared to glucocorticoids alone in giant cell arteritis (The arteritic variety is treated with oral glucocorticoids (prednisone 80 mg orally once a day and tapered based on erythrocyte sedimentation rate and C-reactive protein) to protect the other eye. If there is vision loss, high dose intravenous glucocorticoids should be considered. Treatment should not be delayed while awaiting the biopsy procedure or its results. Results from clinical trials show that tocilizumab given when tapering glucocorticoids improves glucocorticoid-free remission when compared to glucocorticoids alone in giant cell arteritis (1).
There is no established treatment of the nonarteritic variety. Vascular risk factors should be optimized.
Low-vision aids (eg, magnifiers, large-print devices, talking watches) may be helpful in both types.
Pearls & Pitfalls
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Treatment reference
1. Stone JH, Tuckwell K, Dimonaco S, et al. Trial of tocilizumab in giant-cell arteritis. N Engl J Med. 2017;377(4):317-328. doi: 10.1056/NEJMoa1613849
Prognosis for Ischemic Optic Neuropathy
There is no effective treatment for the nonarteritic variety of optic nerve infarction; however, up to 40% of patients have mild spontaneous recovery of vision (1).
In the arteritic variety caused by giant cell arteritis, losses of visual acuity and visual field are typically greater. Prompt treatment does not restore lost vision in the affected eye but protects the unaffected eye. Inadequate treatment risks relapses and additional vision loss.
Prognosis reference
1. Singh S, Zimmerman MB. Nonarteritic anterior ischemic optic neuropathy: natural history of visual outcome. Ophthalmology. 2008;115(2):298-305.e2. doi:10.1016/j.ophtha.2007.05.027
Key Points
Ischemic optic neuropathy is usually caused by atherosclerosis, but giant cell arteritis should always be ruled out.
Suspect ischemic optic neuropathy in patients 55 years and older who have sudden, painless loss of vision.
If giant cell arteritis is suspected, treat immediately with glucocorticoids to decrease the risk of contralateral involvement.
Visual prognosis tends to be poor.
