The Endophthalmitis Population Study of Western Australia (EPSWA): first report

Over the period of 19 years to 1999, cataract surgery numbers increased 6% per annum in Western Australia (WA), promoted by the convenience, efficacy, and general safety of outpatient phacoemulsification surgery. Although endophthalmitis is an uncommon complication, it is a major cause of post-cataract surgery blindness. The present population study investigates not only the prevalence of endophthalmitis but provides an accurate incidence of endophthalmitis in WA over the same period.

Using the hospital morbidity data system (HMDS) of the WA Record Linkage Project, and cross validating against three independent databases (anaesthetic and microbiological databases and surgeons' logbooks) the authors examined 698 case notes that were potentially cases of endophthalmitis for the period 1980 to June 1999. As the database linkage was incomplete for 1999, only the 188 confirmed cases to 1998 were included in the present study. Additional case note validation was performed to confirm the correct codes for the cataract surgical procedure.

Despite changes in surgical technique and prophylaxis over the study period of 19 years, the incidence of endophthalmitis remained largely unchanged, averaging one in 500 surgical cases overall. However, the incidence fluctuated over time and varied with the location of surgery ranging from 0.65 per 1000 operations to 16.4 per 1000 operations.

These data highlight previously undescribed temporal and geographic variations in the incidence of endophthalmitis. It is uncertain whether the wide variation in prophylactic practices throughout the ophthalmic community has any bearing on the incidence of endophthalmitis.