ABSTRACT
An outbreak of post-operative endophthalmitis involving 48 patients from October 1991 to October 1992 in Lampang Hospital was reported. There were 3 waves of clustered cases, i.e. from October 1991 to January 1992, April-June 1992, and August-October 1992. Investigation revealed several risk factors: defects in sterilization of surgical instruments, poor operating room hygiene, contaminated tap water and the use of multiple-dose fluids and medication. Bacteria isolated from vitreous fluid showed different bacteria, indicating multiple sources of infection or failure of asepsis. Each episode of infection was brought under control by removing the risk factors and emphasis on aseptic techniques. The value of an effective survey programme for the detection of post-operative endophthatmitis was emphasized.