ABSTRACT
Optic neuropathy is one of the most feared complications from stereotactic radiosurgery (SRS) or HSRT. Overall, the incidence of optic neuropathy after SRS is low (Sta‰ord et al., 2003; Leavitt et al., 2013; Pollock et al., 2014). e most commonly used constraint for the optic apparatus is 8 Gy (Tishler et al., 1993), but recent data from Mayo Clinic showed that the risk of developing a clinically signi‚cant radiation-induced optic neuropathy was 1.1% for patients receiving a single maximum point dose of 12 Gy or less to the optic apparatus (Sta‰ord et al., 2003). Overall, radiation-induced optic neuropathy developed in less than 2% of patients, despite that 73% received >8 Gy to a short segment of the optic apparatus. In a follow-up study, colleagues from Mayo Clinic found that the risk of radiation-induced optic neuropathy was 0%, 0%, 0%, and 10% when the maximum radiation doses received by the anterior visual pathway were ≤8, 8.1-10.0, 10.1-12.0, and >12 Gy, respectively (Leavitt et al., 2013). e overall risk of radiationinduced optic neuropathy in patients receiving >8 Gy to the anterior visual pathway was 1.0% (Leavitt et al., 2013). In another series from Mayo Clinic where 133 patients (266 sides) with pituitary adenomas were treated with SRS, no optic neuropathy was observed at a median follow-up of 32 months when the maximum point dose to the optic apparatus did not exceed 12 Gy (Pollock et al., 2014).
