An eye and orbit ultrasound is a test to look at the eye area. It also measures the size and structures of the eye.
The test is most often done in the ophthalmologist's office or the ophthalmology department of a hospital or clinic.
Your eye is numbed with medicine (anesthetic drops). The ultrasound wand (transducer) is placed against the front surface of the eye.
The ultrasound uses high-frequency sound waves that travel through the eye. Reflections (echoes) of the sound waves form a picture of the structure of the eye. The test takes about 15 minutes.
There are 2 types of scans: A-scan and B-scan.
For the A-scan:
For the B-scan:
No special preparation is needed for this test.
Your eye is numbed, so you should not have any discomfort. You may be asked to look in different directions to improve the ultrasound image or so it can view different areas of your eye.
The gel used with the B-scan may run down your cheek, but you will not feel any discomfort or pain.
You may need this test if you have cataracts or other eye problems.
An A-scan ultrasound measures the eye to determine the right power of a lens implant before cataract surgery.
A B-scan is done to look at the inside part of the eye or the space behind the eye that cannot be seen directly. This may occur when you have cataracts or other conditions that make it hard for the doctor to see into the back of your eye. The test may help diagnose retinal detachment, tumors, or other disorders.
For an A-scan, measurements of the eye are in the normal range.
For a B-scan, the structures of the eye and orbit appear normal.
A B-scan may show:
To avoid scratching the cornea, do not rub the numbed eye until the anesthetic wears off (about 15 minutes). There are no other risks.
Reviewed By: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.