PURPOSE: To present in vivo anterior segment optical coherence tomography (OCT) features of infants with Peters' anomaly obtained during presurgical examination under general anaesthesia, and to evaluate the impact of OCT features on surgical decision making. METHODS: This is a single-centre, consecutive, observational case series including 44 eyes of 27 infants with Peters' anomaly (5-18 months) undergoing keratoplasty. Medical records of patients were reviewed retrospectively. Clinical features and OCT findings, along with their impact on surgical decision-making were analysed. RESULTS: Of 27 patients, 10 had unilateral and 17 had bilateral disease. Two patients with mild disease (three eyes) had a posterior corneal defect with leukoma (2/27, 7.4%). Twenty patients (32 eyes) with iridocorneal adhesions were classified as having moderate Peters' anomaly (20/27, 74.1%) and five patients (nine eyes) with lenticulocorneal adhesions were classified as having severe Peters' anomaly (5/27, 18.5%). The range of angle closure, anterior chamber depth and maximum iridocorneal adhesion length (all p<0.001) were significantly different among groups, indicating that they might serve as novel OCT parameters for assessing the severity of Peters' anomaly. The surgical approach in seven patients (21.2%) was altered in response to intraoperative OCT findings, which provided information regarding the anatomical structure of the anterior chamber not provided by the surgical microscope. The use of OCT prevented unnecessary cataract surgeries in five patients. CONCLUSIONS: Our study showed that information gained from OCT under anaesthesia allows surgeons to classify type and severity of Peters' anomaly and supports surgical decision making.