How optometrists screen for glaucoma: a survey.

All optometrists registered and practising in Leicestershire were surveyed to find out what facilities they have for glaucoma screening, how patients are selected for screening, what tests are performed, and the criteria used for referring patients to the hospital ophthalmic service. All respondents examine the optic disc of all patients: 99% have tonometry available, but most use it selectively, on the basis of age, family history and disc appearance. Although 88% have field testing apparatus, this is usually not of a type likely to be effective in screening a general population: 38% have automated or semiautomated perimetry. The criterion level of IOP at which 80% of respondents would refer was 27 mm Hg in the absence of disc cupping, falling to 24 mm Hg if cupping was suspected. Over 80% would refer any patient with a field defect irrespective of IOP.