Tonometry is performed on the client with a suspected diagnosis of glaucoma.
The nurse analyzes the test results as documented in the client's chart and understands that normal intraocular pressure is:
- a) 2 to 7 mm Hg
- b) 10 to 21 mm Hg***
- c) 22 to 30 mm Hg
- d) 31 to 35 mm Hg.
The correct answer is b) 10 to 21 mm Hg.
Normal intraocular pressure (IOP) is the fluid pressure inside the eye. IOP is measured in millimeters of mercury (mmHg). Normal IOP is between 10 and 21 mmHg.
Tonometry is a test that measures IOP. The test is usually performed by an ophthalmologist, an eye doctor who specializes in the diagnosis and treatment of eye diseases.
Tonometry is an important part of the eye exam for people at risk of glaucoma. Glaucoma is a group of eye diseases that can damage the optic nerve, the nerve that carries signals from the eye to the brain. If left untreated, glaucoma can lead to vision loss and blindness.
There are two main types of tonometry:
- Applanation tonometry:
This is the most common type of tonometry. It is performed using a device called a tonometer. The tonometer is placed on the cornea, the clear front surface of the eye. The tonometer measures the pressure of the cornea, which is an indirect measure of IOP.
- Non-contact tonometry:
This type of tonometry does not require contact with the cornea. It is performed using a device called an air-puff tonometer. The air-puff tonometer emits a puff of air at the eye. The device measures the pressure of the air rebounding off the cornea, which is an indirect measure of IOP.
Tonometry is a painless test that takes only a few minutes to perform. The results of the test are usually available immediately.
If the results of the tonometry test show that IOP is elevated, the ophthalmologist will order further tests to confirm the diagnosis of glaucoma and determine the severity of the disease. Treatment for glaucoma typically includes medication, laser therapy, or surgery.
