Monitoring the intraocular pressure (IOP) is one of the most important tests used in follow-up among glaucoma suspects and confirmed glaucomatous patients.

In tertiary hospitals, IOP screening is an important tool to confirm glaucomatous eyes. Inaccurate measurements may lead to missed diagnosis or false positive results that may affect patients' quality of life.

There are many devices produced to measure IOP, the commonest one is Goldman contact tonometry, the aim of this study is to compare the results of new developed tonometers to the standard applanation tonometer.

Inclusion Criteria:

• All subjects seeking regular check-up in glaucoma clinic at banha university hospital.
• Glaucoma suspects and glaucomatous patients that visit glaucoma clinic for regular IOP measurements.

Exclusion Criteria:

• Patients that will refuse to measure IOP again with other devices.
• patients with previous corneal surgeries or scar that may alter the measurements of the tonometer s (as previous keratoplasty, trauma or opacities).