الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Elevated IOP is a primary risk factor in the initiation and progression of glaucoma. Therefore, accurate measurement of IOP has an important role in screening, detection and follow up for glaucoma. Recently, several new instruments have been developed to determine IOP as accurately as possible; the recent tonometers try to give an accurate and easy IOP measurement, correlated with conventional tonometers, and at the same time try to overcome other factors such as central corneal thickness, corneal diameter and curvature which may influence it mainly after refractive surgery. These tonometers include: rebound tonometer, the applanation resonance tonometer, the dynamic contour tonometer, and the ocular response analyzer tonometer. Rebound tonometer is a portable, digital and contact tonometer but it has a very small contact area. The ocular response analyzer is a new non contact tonometer which provides a new measurement of corneal tissue properties called corneal hysteresis. ART works on the base of Imbert-Fick law. It is digital, contact, and it can be mounted on the slit lamp or used as a hand held device. Goldmann Applanation Tonometry (GAT) is remained the ‘‘gold standard’’ of clinical evaluation of the intraocular pressure. However, its accuracy may be affected by various corneal or ocular parameters, including central corneal thickness, corneal astigmatism, corneal curvature, and axial length of the eyeball. Other devices should be used only if Goldmann tonometry is not available or if factors are present which would make its use difficult or unreliable. Such as: Non sitting position of the patient: • Perkins tonometer • Dreager tonometers. Abnormal anatomic conditions of the cornea: • Mackay-Marg tonometer. • Tonopen tonometer. • Pneumatic tonometer. Need to measure scleral rigidity: • Schiotz tonometer.