What Is Ocular Ultrasound?
Ocular ultrasound uses sound waves, rather than light, to create an image of the structures inside and around the eye. Because sound waves can pass through tissue that light cannot — including a cloudy lens or blood in the eye — ultrasound is a valuable tool when other imaging methods aren't able to give a clear view of the eye's interior.
Types of Ocular Ultrasound
There are two main types used in eye care:
- A-scan Ultrasound: Produces a one-dimensional reading used primarily to measure the length of the eye and distances between internal structures.
- B-scan Ultrasound: Produces a two-dimensional cross-sectional image of the eye, allowing our providers to visualize the retina, vitreous, and other structures at the back of the eye.
Why It's Used
Ocular ultrasound is especially useful when a cataract, significant bleeding inside the eye, or another condition blocks a clear view of the retina through standard examination or photography. In these cases, a B-scan can help identify issues such as retinal detachment, masses, or other structural changes that would otherwise be difficult to detect. It's also used to evaluate the eye prior to certain surgical procedures.
What to Expect
For most ocular ultrasounds, numbing drops are applied and a small probe is gently placed against the surface of the eye, or sometimes against the closed eyelid, using a small amount of gel to help transmit the sound waves. The test is quick and generally well tolerated, with no significant discomfort and no downtime afterward. Your provider will explain the findings as part of your overall evaluation.