**9.1 Visual function**

In most cases, SOM surgery stabilizes or improves visual function. In a large retrospective study of 130 patients, Terrier *et al.* demonstrated improvement in 45% of cases, stabilization in 39%, and worsening in 16% [28]. Fisher *et al.* highlighted in their meta-analysis that visual acuity and visual field were stabilized or improved in 91% and 87% of cases, respectively [12]. However, these encouraging results must be put into perspective, since improvement does not mean a complete restoration of visual function. Anatomically, invasion of the optic canal is associated with severe visual impairment both preoperatively and postoperatively [29], and tumor extension to the periorbit appears to be a negative predictive factor for visual acuity [8]. Therefore, it is essential to propose surgery to patients with SOM as soon as the optic pathways are threatened by the tumor, so that they can be optimally decompressed.

Regarding oculomotion, the reporting of results is generally less detailed, but seems to indicate a long-term improvement of the preoperative symptomatology that could reach 96% (although the degree of this improvement was not specified) [12]. Postoperative oculomotor deficits are frequent, varying from 8 to 68% depending on the series, but they recover in the majority of cases and persist in only 0–17% of cases [6, 11, 30, 31].
