Tonometry

There are three main methods of measuring eye pressure. The most accurate method measures the force needed to flatten an area of the cornea. The surface of the eye is numbed with eye drops. A fine strip of paper stained with orange dye is held to the side of the eye. The dye stains the front of the eye to help with…

Remove contact lenses before the exam. The dye can permanently stain contact lenses. Tell your provider if you have a history of corneal ulcers or eye infections , or a history of glaucoma in your family. Always tell your provider what medicines you are taking.

If numbing eye drops were used, you should not have any pain. In the noncontact method, you may feel mild pressure on your eye for a brief moment from the air puff.

Tonometry is a test to measure the pressure inside your eyes. The test is used to screen for glaucoma and to measure how well glaucoma treatment is working. People over age 40 years, particularly African Americans, have the highest risk for developing glaucoma. Regular eye exams can help detect glaucoma early. If it…

A normal result means your eye pressure is within the normal range. The normal eye pressure range is 10 to 21 mm Hg. The thickness of your cornea can affect measurements. Normal eyes with thick corneas have higher readings, and normal eyes with thin corneas have lower readings. A thin cornea with a high reading may be…

Abnormal results may be due to: Glaucoma Hyphema (blood in the front chamber of the eye) Inflammation in the eye Injury to the eye or head

If the applanation method is used, there is a small chance the cornea may be scratched ( corneal abrasion ). The scratch will normally heal within a few days.

Chen S, Lee BD, Al-Aswad LA. Clinical examination of glaucoma. In: Yanoff M, Duker JS, eds. Ophthalmology . 6th ed. Philadelphia, PA: Elsevier; 2023:chap 10.4. Knoop KJ, Dennis WR. Ophthalmologic procedures. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and…