The primary objective of this clinical study is to prove that tonometry values for NIDEK TONOREF III are comparable to the predicate device and to prove that the pachymeter function of NIDEK TONOREF III is equivalent to the predicate device. The secondary objective is to demonstrate that the test device is as safe as the predicate devices.

Exclusion criteria

1. Subjects with only one functional eye;
2. Those with one eye having poor or eccentric fixation;
3. Those with corneal scarring or who have had corneal surgery including corneal laser surgery;
4. Microphthalmos;
5. Buphthalmos;
6. Contact lens wearers;
7. Dry eyes;
8. Lid squeezers - blepharospasm;
9. Nystagmus;
10. Keratoconus;
11. Any other corneal or conjunctival pathology or infection.
12. central corneal thickness greater than 0,600 mm or less than 0,500 mm (2 standard deviations about the human mean)