A review of radiation-induced optic neuropathy (RION) by Auckland University’s Professor Helen Danesh-Meyer and Dr Dineo Mpe has highlighted it as a cause of vision loss with a lack of good prophylaxis or treatment.

RION, a late complication of radiotherapy cancer treatment, is a rare but devastating condition typically presenting with painless vision-loss in one or both eyes, peaking one to two years after radiation exposure. Although its pathogenesis is not yet fully understood, it is thought RION occurs through delayed radiation-induced ischaemic necrosis from free radical damage, said the authors.

Hyperbaric oxygen therapy is suggested as one, controversial, RION treatment, with overall results “disappointing”. “However, systemic or intravitreal anti-VEGF may have a role in improving or stabilising vision.” Since using radiation levels within strict parameters can limit RION incidence to around 1–2%, meticulous planning with today’s more precise radiotherapy technologies is essential, the authors concluded.