Current concepts in the diagnosis, pathogenesis and management of nonarteritic anterior ischaemic optic neuropathy

Abstract

Nonarteritic anterior ischaemic optic neuropathy (NAION) is the most common acute optic neuropathy in patients over the age of 50 and is the second most common cause of permanent optic nerve-related visual loss in adults after glaucoma. Patients typically present with acute, painless, unilateral loss of vision associated with a variable visual field defect, a relative afferent pupillary defect, a swollen, hyperaemic optic disc, and one or more flame-shaped peripapillary retinal haemorrhages. The pathogenesis of this condition is unknown, but it occurs primarily in patients with structurally small optic discs that have little or no cup and a variety of underlying vascular disorders that may or may not be known at the time of visual loss. There is no consistently beneficial medical or surgical treatment for the condition, but there are now animal models that allow testing of various potential therapies. About 40% of patients experience spontaneous improvement in visual acuity. Patients in whom NAION occurs in one eye have a 15-19% risk of developing a similar event in the opposite eye over the subsequent 5 years.

Corticosteroids and Anti-Complement Therapy in Retinal Diseases

“…Diagnosis is made in part by serology for antibodies against the organism. Final visual outcome was equal to or better than 20/40 in about 68% of patients, and poor vision, equal to or less than 20/200, was observed in 5%; treatment did not Medications that have been associated with the development of NAION include interferon-α, erectile dysfunction drugs, and amiodarone, although the cause and effect relationship is not entirely convincing as the affected individuals may have confounding risk factors (Miller and Arnold 2015). The optic disc in the affected eye exhibits swelling, often with peripapillary hemorrhages, and the optic disc in the unaffected eye typically exhibits a crowded appearance with a small cup and has been called in the literature a "disc at risk.…”

“…A plethora of medical and surgical therapies, including hyperbaric oxygen, optic nerve sheath fenestration, optic neurotomy, diphenylhydantoin, aspirin, corticosteroids both systemic and intravitreal, anti-VEGF agents, and erythropoietin, have been used in NAION without convincing data for any therapeutic benefit (Miller and Arnold 2015). Evaluation and treatment for modifiable risk factors is perhaps the best care that a clinician can provide to their patient (Miller and Arnold 2015).…”

“…Evaluation and treatment for modifiable risk factors is perhaps the best care that a clinician can provide to their patient (Miller and Arnold 2015). The goal is to decrease the risk of fellow or second eye involvement in NAION, estimated to be around 15%, since bilateral NAION will likely produce significant morbidity and life changes to the patient.…”

Is There A Role for Intravitreal Pharmacotherapy in the Treatment of Acute Nonarteritic Ischemic Optic Neuropathy?

“…Several treatment modalities, targeting decompression, neuro protection or anticoagulation were tried but no convincing treatment effect could be demonstrated [9] .…”

“…However, a prevalent anatomic finding of a small or absent physiologic cup, which is common known as 'disc at risk', seems to play also an important role [6,7] . In combination with other atherogenic and vasoconstrictive risk factors such as hypertension, sleep apnea syndrome, diabetes, dyslipidaemia an ischemic nerve fiber swelling in a tight -looking disc leads to a vicious cycle of ischemia and disc edema [1,2,[6][7][8][9] .…”