Prevalence of glaucoma in the west of Ireland.

County Roscommon in the west of Ireland is a relatively remote rural area whose population of 55,000 is served by two community medical ophthalmologists and three optometrists. Eye surgical services are not available within the county. In order to assess the needs of the community for prevention of blindness from glaucoma, a simple random sample of the population of County Roscommon was taken for a community based glaucoma survey. A total of 2186 people over the age of 50 were examined which represented a 99.5% response rate. The high response rate was achieved by the community basis of the study and vigorous follow up of non-attenders. Intraocular pressure was measured using applanation tonometry, disc evaluation by both direct ophthalmoscopy and stereoscopic biomicroscopy, and visual field analysis using the Henson CFS 2000 and experimental computer controlled video perimetry. Diagnostic criteria were consistent with the preferred practice pattern of the American Academy of Ophthalmology. A crude prevalence of approximately 2% for primary open angle and normal tension glaucoma was found. The population profile of intraocular pressure showed a pattern which decreased with increasing age unlike the Framingham and Ferndale studies but similar to Japanese data.