Tonometers are essential ophthalmic instruments designed to accurately measure intraocular pressure (IOP), a critical diagnostic tool for detecting and managing glaucoma and other eye conditions. Available in types like Goldmann applanation, non-contact air-puff, handheld rebound (e.g., iCare), and Schiotz indentation models, they assess pressure in mmHg (normal range: 10-21) via gentle corneal contact or air displacement, ensuring patient comfort with topical anesthetics. Portable electronic versions offer quick, reliable readings for clinics, pediatrics, or field use, while slit-lamp integrated units provide precision during routine exams. Featuring user-friendly designs, calibration scales, and disposable tips to minimize infection risks, tonometers enable early intervention, monitoring treatment efficacy, and preventing vision loss in diverse patient populations.