Rapidly progressive non-arteritic anterior ischaemic optic neuropathy

Correspondence to Dr Jonathan A Micieli; jonathanmicieli@gmail.com Description Non-arteritic anterior ischaemic optic neuropathy (NAION) typically presents with sudden painless vision loss in those with vascular risk factors and a ‘disc-at-risk’.1 Following the initial insult, most patients remain stable or may notice slight improvement in their vision. Progression was previously defined by Arnold et al as worsening of visual acuity by at least three lines or at least 3.0 dB on quantitative perimetry during the first 30 days after initial vision loss and has been reported to occur in the range of 22%–37%.4 A number of smaller case series have described cases in more detail such as Borchert and Lessell who described a series of eight patients that had progression of NAION over weeks to months.5 Beck et al documented three cases that progressed between 1 and 3 weeks after onset.6 Our case stands out as the progression occurred rapidly within 1 week of initial symptom onset and the progression took his entire visual field after an initial inferior altitudinal defect. The presence of optic disc oedema creates more crowding at the optic nerve head and the swollen axons may further compromise blood flow providing an explanation for this occurrence.7 8 Unfortunately, there is no established treatment for NAION9 and there was no evidence the optic nerve decompression was helpful even in those with progressive NAION.2 Although NAION is typically thought of as a non-progressive disease, this case demonstrates that it can progress when the optic disc remains oedematous.