Primary open angle glaucoma afflicts 1-2% of people over 50 years of age. The diagnosis relies on a number of examinations, many of them performed by ophthalmic nurses, and the care of glaucoma patients has become one of their main tasks. A knowledge-based system for decision support in glaucoma management has been developed and validated. The aim of the current study is to evaluate the influence of computerised decision support on a 'shared care' organisation for the management of glaucoma patients.