Alternative names
Echography - eye; Ultrasound - eye

Definition

In this test, the eye is examined by ultrasound. The ultrasound uses high-frequency sound waves that are emitted and received by a hand-held instrument called a transducer. The sound waves travel through the eye.

Reflections (echoes) of the sound waves returning to the transducer form a picture of the structure of the eye. The precise size of the eye and any structures in the eye can be measured.

How the test is performed

The test is usually done in the ophthalmologist’s office or the ophthalmology department. You usually sit in a chair. The eye will be numbed with anesthetizing drops. The transducer is placed against the front surface of the eye.

For the A-scan, you will be asked to look straight ahead. If a B-scan is performed, you will be asked to look in multiple directions. A lubricant placed on the transducer may run on your cheek, but there will be no discomfort or pain. The test takes about 15 minutes.

How to prepare for the test
No special preparation is necessary for this test.

In infants and children:
The preparation you can provide for this test depends on your child’s age, previous experiences, and level of trust. For general information on how you can prepare your child, see the following topics:

 
• Infant test or procedure preparation (birth to 1 year)  
• Toddler test or procedure preparation (1 to 3 years)  
• Preschooler test or procedure preparation (3 to 6 years)  
• Schoolage test or procedure preparation (6 to 12 years)  
• Adolescent test or procedure preparation (12 to 18 years)

How the test will feel
Your eye is numbed, so no discomfort is involved. You may be asked to look in a different directions to improve the ultrasound image or to view different areas of the eye.

Why the test is performed

The ultrasound helps evaluate the farthest part of the eyeball when you have cataracts or other reasons that make it hard to look into your eye. The test may help diagnose retinal detachment or other disorders when the eye is not clear and the ophthalmologist can not use routine examining equipment. An A-scan ultrasound measures the eye for the proper power of a lens implant before cataract surgery.

Normal Values
The structures of the eyeball appear normal.

What abnormal results mean

The test may reveal:

 
• Vitreous hemorrhage (bleeding into the transparent gel that fills the eyeball between the retina and the lens)  
• Retinal detachment (separation of the retina from the middle coat of the eyeball),  
• Tumors such as retinoblastoma (cancerous growth of retinal cells) or melanoma (cancerous growth under the retina or other parts of the eye)  
• Lesions in the orbit (the bony socket that protects the eye)  
• Foreign bodies  
• Inflammation

What the risks are
To avoid scratching the cornea, do not rub the anesthetized eye until the anesthetic wears off (about 15 minutes). There are no other risks.

Medical Encyclopedia

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.