Background The purpose of this study was to report the incidence, time after inciting event, aetiology and risk after specific intraocular procedures and the visual outcomes associated with sympathetic ophthalmia (SO) occurrence. Methods This study reports data from multiple retrospective cohorts: retrospective population-based data were extracted from the TRICARE service network (between 2017 and 2021) and retrospective case-based data from the Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) database (cohorts from the UK, South India and North India). Results There were 159 patients with SO identified. The length of time from sensitising event to SO occurrence was a median of 151 days (range: 6–9100 days). In the TRICARE database, 2 patients developed SO after open globe trauma and primary repair (of 615 eyes, rate 0.33%; 95% CI 1.26% to 1.30%). None developed SO after vitrectomy (total of 23 903 events; 95% CI 0% to 0.012%). The combined North Indian and UK cohorts reported 78.6% (81 patients) after trauma, 18.45% (19 patients) after elective surgery. Visual outcomes were reported in the OASIS database for 98.01% of patients (155 of 157 patients). The median presenting and final best corrected visual acuity (BCVA) for the inciting eye were no perception of light, the median presenting and final BCVA for the sympathising eye were 0.65 and 0.3 logMAR, respectively. Conclusion This study identified 159 cases of SO. With poor visual outcomes in the inciting eye, early diagnosis and management are crucial for optimising visual outcomes in the sympathising eye.