PurposeTo investigate whether new classes of glaucoma medication have influenced glaucoma filtration surgery over a 20-year period in the southeast region of Ireland.MethodsAll patients undergoing glaucoma filtration surgery between January 1986 and December 2005 in Waterford Regional Hospital were identified. The following data were recorded for each patient: age; sex; and type of filtration procedure.ResultsOver the 20-year study period two consultant ophthalmic surgeons performed a total of 760 glaucoma filtration procedures on patients aged over 20 years. The annual average number of glaucoma surgeries declined steadily, defined by availability of different topical anti-glaucoma medications, from an average of 23.75 surgeries per surgeon per year in the subperiod 1986–1995, to 21 in 1996, 20 in 1997, and 12.69 surgeries per surgeon per year in 1998–2005, these differences being statistically significant (general linear model, P<0.001). The age profile of patients did not change significantly over the course of the study period.ConclusionsThe volume of patients requiring glaucoma filtration surgery under the care of two consultant ophthalmic surgeons decreased over the 20-year study period, an era in which three classes of anti-glaucoma medications were made available. However, an increase in the age profile of patients undergoing glaucoma filtration surgery during the same period was not observed. Further study is required to resolve whether introduction of the new topical anti-glaucoma medications has led to a real reduction in the demand for glaucoma filtration surgery, or has just led to the deferral of such a demand.