If the NCT reading is above what value, does it indicate high pressure?

• A. Over 20
• B. Over 25
• C. Over 30
• D. Over 35

Answer: (C)

Non-contact tonometry estimates intraocular pressure (IOP) using an air puff and reports in millimeters of mercury. A normal IOP range is roughly 10–21 mmHg. When the reading climbs above about 30 mmHg, it is considered high pressure, signaling a need for further evaluation for glaucoma risk. Keep in mind that NCT readings can be influenced by corneal thickness and other factors, so a high result should be confirmed with a more precise test like Goldmann applanation tonometry and considered alongside other risk factors. This is why the threshold used here is 30 mmHg.