How to measure intraocular pressure: applanation tonometry

Abstract

All adults attending an eye unit should have their intraocular pressure (IOP) measured, unless there is a contraindication (e.g. trauma or corneal ulcer). Many people with glaucoma have no symptoms and do not know they have the condition. All children who have had cataract surgery should also have their IOP measured at every follow-up visit, if possible. Finding glaucoma early allows treatment to be given which will preserve sight. Although elevated IOP is not the only sign of glaucoma, measuring it is simple and quick to do. It should therefore be done routinely on all adults attending eye care facilities. Applanation tonometry, described in this article, is the preferred method (the ‘gold standard’). Schi$oUtz tonometry, which will be described in a future issue, is a useful screening test which can be performed by nurses or ophthalmic technicians.