Table 1.

Definitions of glaucoma and ocular hypertension

		Open angle glaucoma
Pathology	Ocular hypertension	Primary open angle glaucoma	Normal tension glaucoma
Raised intraocular pressure	Yes	Yes	No
Optic disc changes or visual field defects, or both	No	Yes	Yes
Symptoms	No	<50% at diagnosis	<50% at diagnosis