We are testing the accuracy of Reichert's Tono-Vera tonometer by comparing measurements of IOP with this device and measurements with other commonly-used tonometers, including Goldmann Applanation and iCare.

This is a comparative study between the TonoVera, the gold standard Goldmann Applanation Tonometry (GAT) and an established rebound tonometry device, iCare. IOP measurements will be obtained using the following devices: Reichert's prototype Tono-Vera Rebound tonometer (a rebound tonometer in development), iCare's iC100 rebound tonometer (a device commonly used in clinical practice), GAT (a device commonly used in clinical practice). Reichert's iPac Handheld Pachymeter (a device commonly used in clinical practice) will be used to measure the test subject's Central Corneal Thickness (CCT), measured in µm if CCT is not already on file. An Autorefractor Keratometer (ARK) (a device commonly used in clinical practice) will be used to measure necessary vision correction and corneal curvature. The Ocular Response Analyzer (a device commonly used in clinical practice) will be used to measure corneal hysteresis. Multiple IOP measurements will be taken with each device on each eye for all subjects: 3 along the central cornea, 3 along the peripheral cornea, and 3 along the sclera.

Inclusion Criteria:

• Ability to provide signed and dated informed consent form. Patients willing to comply with all study procedures and be available for the duration of the study.

Male or female patients aged 18 to 99 Patients in good general health as evidenced by ability to come to their appointment on day of study.

Exclusion Criteria:

• Patients age less than 18 years Patients unable or unwilling to provide informed consent to participate in the study Patients for which an accurate tonometry reading cannot be performed. This may include those with blepharospasm (lid squeezers), nystagmus, extensive corneal pathology, or contact lens wearers who cannot remove their contact lens.Patients with significant scleral thinning Patients with a known allergy to proparacaine or fluorescein as these are used to anesthetize and allow measurement respectively of the eye when used with the Goldmann tonometer.