Pathogenesis of Classical Non-arteritic Anterior Ischemic Optic Neuropathy

Unusual combination of bilateral ischaemic optic neuropathy following cardiac surgery

“…Arteritic ION is seen in the context of large vessel vasculitis while non-arteritic ION results from non-inflammatory small vessel disease. It is non-arteritic ION that accounts for the vast majority of cases seen in association with cardiopulmonary bypass and which will form the basis of further discussion 2. In arteritic ION, there will be increased level of C reactive protein (CRP) and erythrocyte sedimentation rate (ESR), while there could be deranged full blood count level due to chronically persistent inflammatory disease, especially when associated with polymyalgia rheumatic which has a 15% chance of giant cell arteritis.…”

“…The most widely accepted theory is that vascular insufficiency of the small blood vessels supplying the optic nerve results in ischaemic damage during periods of bypass-related hypoperfusion. The occurrence of AION or PION is dependent mainly on the location of the affected vessels that supply the optic nerve segments 2. AION results from hypoperfusion in the region of the posterior ciliary artery with subsequent oxygen deprivation of the optic nerve head anterior to the lamina cribrosa.…”

“…AION results from hypoperfusion in the region of the posterior ciliary artery with subsequent oxygen deprivation of the optic nerve head anterior to the lamina cribrosa. It has two subtypes: arteritic ischaemic optic neuropathy secondary to vasculitis, and non-arteritic ischaemic optic neuropathy secondary to non-inflammatory small vessel disease 2. The latter is the most common type of AION and is most commonly seen in the setting of cardiopulmonary bypass-associated visual loss.…”

“…Targets include reducing thrombosis, inducing vasodilation of the optic nerve vasculature or reducing disc oedema. Potential treatments include antiplatelets, vasodilators or steroids 2. The most effective proposed therapeutic method is to control and minimise perioperative risk factors that can contribute to non-arteritic ION and to avoid preoperative anaemia which can exacerbate ischaemia during periods of intraoperative hypotension 7…”

Chronic relapsing inflammatory optic neuropathy: an underdiagnosed cause of recurrent vision loss

“…Our patient was first misdiagnosed with NA-AION, a relatively common cause of optic neuropathy, although she did not have any of the known risk factors, including agerelated macular degeneration, retinal vein occlusion, nocturnal hypotension (i.e., use of arterial vasodilators), or systemic diseases such as hypertension, obstructive sleep apnea, diabetes mellitus, or ischemic heart disease. 6 Most important, the diagnosis of NA-AION was less evident after the relapse, the recurrence, and the worsening of vision loss when the patient was off steroids. Although pain is a common feature of inflammatory optic neuropathy, especially with involvement of the orbital tissues surrounding the optic nerve, a few patients with little or no pain were reported.…”