Objective Quantitative data on visual outcomes after trans-sphenoidal surgery is lacking in the literature. This study aims to address this by quantitatively assessing visual field outcomes after endoscopic trans-sphenoidal pituitary adenectomy using the capabilities of modern semi-automated kinetic perimetry. Methods Visual field area (deg 2 ) calculated on perimetry performed before and after surgery was statistically analysed. Functional improvement was assessed against UK driving standards. Results Sixty-four patients (128 eyes) were analysed (May 2016–Nov 2019). I4e and I3e isopter area significantly increased after surgery ( p  < 0.0001). Of eyes with pre-operative deficits: 80.7% improved and 7.9% worsened; the median amount of improvement was 60% (IQR 6–246%). Median increase in I4e isopter was 2213deg 2 (IQR 595–4271deg 2 ) and in I3e isopter 1034 deg 2 (IQR 180–2001 deg 2 ). Thirteen out of fifteen (87%) patients with III4e data regained driving eligibility after surgery. Age and extent of resection (EOR) did not correlate with visual improvement. Better pre-operative visual field area correlated with a better post-operative area ( p  < 0.0001). However, the rate of improvement in the visual field area increased with poorer pre-operative vision ( p  < 0.0001). Conclusions A median visual field improvement of 60% may be expected in over 80% of patients. Functionally, a significant proportion of patients can expect to regain driving eligibility. EOR did not impact on visual recovery. When the primary goal of surgery is alleviating visual impairment, optic apparatus decompression without the aim for gross total resection appears a valid strategy. Patients with the worst pre-operative visual field often experience the greatest improvement, and therefore, poor pre-operative vision alone should not preclude surgical intervention.