The prescription of anti-glaucoma drugs varies widely between different parts of Sweden, despite similar management principles. No explanation to this has yet been offered. The present study examines if differences in degree or type of glaucoma could be the reason for the differences in drug prescription. Clinical data, including intra-ocular pressure (IOP), visual acuity and resolution field (VF) results, were collected retrospectively form 100 patients, followed for at least 50 months, fifty from a clinic with low and fifty from a clinic with high prescription. All patients had been examined with resolution visual fields at least once a year. There was no significant difference regarding age, gender, number of treated patients, number of prescribed drugs per patient, initial VF findings, initial IOP or follow-up time between the two groups. Significantly more patients had congenital glaucoma and/or family history of glaucoma at the clinic with high prescription. The mean VF result was unchanged and the IOP was significantly lower at the end of follow-up period in this clinic, compared to the clinic with low prescription. However, the mean number of anti-glaucoma drugs per patient was not significantly different between the clinics. These preliminary observations indicate that the difference in anti-glaucoma drug prescription rate between the studied clinics reflects difference in the number of glaucoma cases in the population, presumably due to genetic factors. The mean VF results were better at the clinic with high prescription rate, despite similar mean number of anti-glaucoma drugs per patient. No difference in prescription practice was detected.