The eye of the beholder: exploring the dynamics of regional differences in cataract treatment

Research into the variance in healthcare practice in general focuses on the regional differences over a period of single year. By this focus it leaves out the dynamic nature of the interaction between demand and supply of healthcare. The dynamics of the interaction between demand and supply of cataract treatment in the Netherlands are explored in this paper. This study was initiated by the Dutch Health Care Insurance Board in order to improve policies for managing the Dutch healthcare system. With the use of group model building, a system dynamics model is created to generate insight into the growing number of cataract treatments and differences in the number of treatments between regions. The main source for the growth in number of cataract treatments is a gradual change in indication criteria. The simulations for the twelve provinces in the Netherlands show comparable behaviour. The timing between the simulations is different. Hence the distribution of the number of treatments over the provinces is different for each year. A possible source for difference in timing is the ratio between the population of a province and the number of ophthalmologists in that province. Hence, for assessing the variation of practice time studies are required