The authors of this paper reviewed patient case notes to determine visual outcome following shunt surgery for idiopathic intracranial hypertension (IIH). A retrospective case notes review was conducted for 50 patients who underwent shunt surgery for IIH. Outcome measures included decimal visual acuity and the mean radial degrees (MRD) of the 14e isopter of the Goldman visual field. These values were measured preoperatively and after a mean follow-up period of 1123 days. The mean number of surgical procedures for each patient was 2.8. The mean decimal visual acuity of the worse affected eye improved from 0.75 to 0.84. The MRD score of the worse affected eye improved on average from 25.6 to 35.5 degrees. In summary, shunting can improve visual function in patients with IIH. There is a need for a randomised controlled trial to further investigate operative interventions in IIH. The authors present a sample size calculation for such a trial.