What do you need to know about ocular ultrasound?
Ocular ultrasound is a rapid, non-invasive test commonly used in clinical practice to assess the structural integrity and pathology of the eye. It can provide additional information not easily obtained by direct visualization of ocular tissues and is particularly useful in patients with pathology that prevents or obscures ophthalmoscopy (e.g., large corneal opacities, dense cataract or vitreous hemorrhage).
An eye and eye socket ultrasound uses high-frequency sound waves to measure and produce detailed images of the eye socket.
What does ocular ultrasound involve?
Ultrasound images can be obtained through the patient’s eyelids or with the probe directly on the surface of the eye with appropriate topical anesthesia. The patient must look in the direction of the quadrant to be assessed. The probe rotates around the globe so that the sound waves always pass through the center of the eye. This rotational movement will maximize the amount of retina visualized during the scan.
There are two parts to the ultrasound of the eye and orbit. The A-scan mode takes measurements of the eye and is used for ocular biometry. The B-scan mode is used for cross-sectional information of the eyeball and orbit, allowing the doctor to see structures in the fundus. The combined procedure (A and B) will take 15-30 minutes to complete, the two types of scans being complementary.
A-Scan
A-scan mode measures the eye. This helps determine the correct lens implant for cataract surgery. While sitting upright in a chair, you will place your chin on a support and look straight ahead. An oil probe will be placed on the front of the eye while it is scanned. An A-scan can also be performed while lying down.
B-Scan
The B-scan helps the doctor see the space behind the eye. Cataracts and other conditions make it difficult to see the fundus. B-scan also help diagnose tumors, retinal detachment and other disorders. During a B-scan, you will stay with your eyes closed. The ophthalmologist will apply a gel on your eyelids, and you will keep your eyes closed while moving your eyeballs in different directions.
What can be diagnosed with ocular ultrasound?
Your ophthalmologist may request eye examinations if you have unexplained problems with your eyes or if you have recently suffered an injury or trauma to your eye area. This procedure is useful for diagnosing eye diseases. Some of the disorders that ultrasound helps us identify are:
- tumors or neoplasms involving the eye
- foreign substances
- retinal detachment
An ultrasound of the eye and eye socket may also be used to help diagnose or monitor:
- glaucoma (a progressive disease that can lead to vision loss)
- cataract (clouding of the lens)
- lens implants (artificial lens implanted in the eye after removal of the natural lens, usually due to cataract)
The doctor may also use this procedure to measure the thickness and extent of a cancerous tumor and determine treatment options.