Population based glaucoma screening

Glaucoma is a common eye disease that causes glaucomatous optic neuropathy with subsequent visual field loss, and can eventually lead to irreversible blindness. Early stages do not cause any symptoms, and visual field loss often goes unnoticed initially. Patients become aware of their eye disease only after extensive damage has occurred. Therefore, screening seems a logical approach to reduce the glaucoma burden. At present, a glaucoma screening programme does not exist in the Netherlands, but opportunistic case finding by ophthalmologists, optometrists, and opticians has become common practice. Despite case finding, about half of all glaucoma cases are currently undetected and thus do not receive any treatment or monitoring. Population based glaucoma screening could help identify these individuals. However, cost-effectiveness studies regarding glaucoma screening indicate that economic viability is dubious. In this thesis, several factors are identified that have a further negative impact on the cost-effectiveness of glaucoma screening. These factors are: lengthbias, suboptimal by-patient test specificity, and large clinical workload from false positives. This leads to the conclusion that at present population based glaucoma screening is not feasible in the Netherlands. One of the studies of this thesis shows that the major part of Dutch inhabitants over age 40 visits an optician regularly, and that opticians are willing to participate in glaucoma screening. Optician based screening is therefore a promising alternative to population based screening, and will be subject of further research projects.