Bryan Tan, Jonathon Ng, Antony Clark, Nigel Morlet
Purpose: Whole-population studies are the best study design to determine health services trends. Understanding trends in glaucoma surgery is impor- tant to properly plan eye services for an ageing pop- ulation. Our aim was to describe glaucoma surgery trends in a whole population.
Methods: All trabeculectomies and tube operations undertaken in Western Australia in 1992 to 2013 were identifted using linked hospital data from the Western Australian Data Linkage System. Age and sex standardized incidence rates were calculated by direct standardization to the 2013 Western Australian population. Poisson regression was used to calculate incidence rate ratios adjusting for age, sex and year.
Results: Over 21-years annual trabeculectomy inci- dence decreased 7% (incidence rate ratio [IRR] 0.93, p-value<0.001) with an incidence of 32/100,000 PY in 1992 versus 13/100,000 PY in 2013. Over the same period tube operations increased 15% (IRR 1.15, p-value<0.001) with incidence of 0.07/100,000 PY in 1992 versus 4.4/100,000 PY in 2013. Since 2000, the decreasing trabeculectomy incidence slo- wed markedly (IRR 0.98) compared to before 2000 (IRR 0.91). Men were more likely to have trabecu- lectomy (IRR 1.11, p-value<0.001) and tube surgery (IRR 1.25, p-value 0.003) than women. Incidence increased in older age groups for trabeculectomy and tube surgery. Conclusion: Incidence of trabeculectomy decreased over 21-years but remained overwhelmingly more common than tube surgery. The marked decrease in trabeculectomies in the late 1990s coincided with the introduction of topical prostaglandin analogues.