What is the normal range for intraocular pressure measured by tonometry?

What is the normal range for intraocular pressure measured by tonometry?

• A. 10-21 mm Hg
• B. 5-9 mm Hg
• C. 22-30 mm Hg
• D. 0-4 mm Hg

Answer: (A)

Normal intraocular pressure measured with tonometry is about 10 to 21 mm Hg. This range is what most healthy eyes maintain, though individual factors like diurnal variation and corneal thickness can cause small fluctuations. Readings above roughly 21–22 mm Hg are considered elevated and may signal glaucoma risk, while very low pressures (0–4 mm Hg) are not normal and can point to hypotony. A reading like 5–9 mm Hg is typically low for a healthy eye, and 22–30 mm Hg is elevated. So, the standard normal range is 10–21 mm Hg.

Normal intraocular pressure measured with tonometry is about 10 to 21 mm Hg. This range is what most healthy eyes maintain, though individual factors like diurnal variation and corneal thickness can cause small fluctuations. Readings above roughly 21–22 mm Hg are considered elevated and may signal glaucoma risk, while very low pressures (0–4 mm Hg) are not normal and can point to hypotony. A reading like 5–9 mm Hg is typically low for a healthy eye, and 22–30 mm Hg is elevated. So, the standard normal range is 10–21 mm Hg.