Tonometer is an ophthalmic diagnostic instrument used to measure intraocular pressure (IOP) inside the eye. It is an essential tool for eye examinations and plays an important role in screening and monitoring conditions such as glaucoma, where elevated eye pressure can contribute to optic nerve damage. Tonometers are available in different types, including applanation and non-contact models, and are widely used in ophthalmology and optometry clinics for accurate and efficient eye pressure assessment.