Anterior Ischaemic Optic Neuropathy (AION)

Suspected anterior ischaemic optic neuropathy (AION) should always be reviewed by an ophthalmologist, even if the visual acuity is currently normal, to ensure aggressive treatment and continual monitoring.

If giant cell arteritis is the suspected cause of AION, the use of high dose steroids is thought to reduce inflammation and preserve blood supply to the optic nerve head.

However, there is a void of evidence regarding this well recognised and routine therapy. This is due to the unethical nature of conducting controlled trials in light of the multiple case report and cohort studies suggesting benefit from the mid-twentieth century.

Treatment

Two reviews [22, 23] have found no good evidence to support the use of intravenous over high dose oral steroids in AION.

Therefore, emergency treatment in the ED should comprise of early identification, prompt referral for temporal artery biopsy and immediate initiation of high dose oral prednisolone.

Although there is no direct consensus regarding the optimum regimen for oral steroid dosing, a pragmatic regime would be 1 mg/kg/day oral prednisolone aiming to taper after four weeks.

Learning bite

Although debate is ongoing, current evidence is not of sufficient quality to routinely recommend IV over high dose oral corticosteroid preparations in the treatment of arteritic AION.