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.

Inclusion Criteria:

1. be at least 18 years of age of either sex and any race or ethnicity;
2. be willing and able to provide written informed consent prior to any study procedures being performed;
3. be willing and able to follow all instructions and attend all study visits;

Exclusion Criteria:

1. have only one functional eye;
2. have poor or eccentric fixation in either eye;
3. have corneal scarring or have had corneal surgery, including corneal laser surgery in either eye;
4. have microphthalmos in either eye;
5. have buphthalmos in either eye;
6. be a contact lens wearer, meaning having worn soft contact lenses within the past 3 months and/or rigid permeable gas lenses within the past 6 months;
7. have dry eyes, meaning having been diagnosed by a physician with dry eyes and currently using a prescribed medication or daily use of artificial tears;
8. be a lid squeezer - blepharospasm;
9. have nystagmus in either eye;
10. have keratoconus in either eye;
11. have any other corneal or conjunctival pathology or infection in either eye;
12. have a condition or a situation, which in the Investigator's opinion, may put the subject at increased risk, confound study data, or interfere significantly with the subject's study participation.