The Tono-Vera Tonometer (Reichert, Inc.) is a portable rebound tonometer intended to measure IOP. Subjects will undergo a standard ophthalmologic examination. Subjects will then be measured with four tonometers: Goldmann Applanation Tonometer (C.S.O. SRL), Ocular Response Analyzer G3 (Reichert, Inc.), iCare ic100 tonometer (iCare Finland Oy), and Tono-Vera Tonometer.