How to measure intraocular pressure: applanation tonometry

Unless there is a contraindication (e.g. trauma or corneal ulcer), all adults attending an eye unit should have their intraocular pressure (IOP) measured. 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. Applanation tonometry, using a Goldmann tonometer at a slit lamp, is the preferred method (the ‘gold standard’).