Tonometry in question: can visual screening tests play a more decisive role in glaucoma diagnosis and management?

Chronic open-angle glaucoma is a disease in which characteristic changes occur in optic nerve morphology and in ganglion cell function. The utility of intraocular pressure readings in the diagnosis and ongoing management of glaucoma patients is pragmatically considered in the light of the availability of potentially more sensitive means of glaucoma monitoring. Conservative appraisal of the literature suggests that traditional clinical tonometry has low diagnostic sensitivity and specificity. The majority of new cases of glaucomatous visual field loss are most likely to arise from the normotensive population. Clinical studies to determine the correlation between intraocular pressure reduction and the preservation of visual function have repeatedly yielded a much weaker association between these two variables than is perhaps generally assumed. Newer psychophysical methods may have greater potential for rapidly identifying and subsequently monitoring glaucoma patients, but still require refinement and more widespread clinical evaluation. One prerequisite for the eventual adoption of such methods is that clinicians fully appreciate the limitations inherent in tonometry as a glaucoma screening and monitoring technique.