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Ultrasound Examination of the Eye

An ultrasound scan of the eye (also called ocular echography) is a simple, painless procedure. A scan may take between 5 and 20 minutes to do.

There is a regular ultrasound clinic in Windsor eye clinic (Windsor Building, Level 1, LRI) on Thursday afternoons run by Mr Barnes or Mr Dehaene.

Scans are also done by many of the eye specialists during the course of daily eye clinics - especially medical retina and surgical retina clinics, and eye emergency clinics.

What happens if I need an ultrasound scan?

Book in at the eye clinic reception, just like a normal eye clinic visit, and your vision will be checked. You will then be asked to sit in the waiting area until called for the scan.

Sometimes dilating drops will be used, which will blur vision for a few hours, but often these are not necessary.

The ultrasound scanner head is about the size of a large toothpaste tube. It is held by the doctor and placed on the eye.

Many scans are done through the closed eyelids, which is easier for young or sensitive patients.

A blob of clear gel is used on the ultrasound head, to give a good contact with the eyelid. It feels wet, and is easily wiped off afterwards.

Sometimes the scan is done directly on the eyeball to give a more detailed image. In this case, local anaesthetic drops are put in the eye, which numbs the surface for a few minutes. The doctor will ask you to look in different directions with both eyes open and gel will be used between the ultrasound head and your eye. The gel is harmless in the eye (it is also used by people who have dry eyes to lubricate and protect the eye).

The scan is usually done in a sitting position, but sometimes it is necessary to lie down and a lot of gel may be put on your eye while you look at the ceiling. Occasionally in this situation a lid guard can be used to help to keep the eyelids out of the way of the scan - if blinking could interfere.

The ultrasound doctor will file the scan report in your hospital notes and write to the referring doctor (who requested the scan). If necessary, you will have a follow-up appointment in the clinic where you were previously seen.

The ultrasound doctor will help with any queries where they can, but may not be able to answer questions about your eye condition. The referring doctor will have examined your eye thoroughly and may be expecting results from other tests before coming to a conclusion. A follow-up appointment will be made if you need to discuss things further.

If the scan was done directly onto the surface of your eye, it is not unusual to feel a little dry, gritty or sore afterwards. Any such discomfort should be mild and should have settled by the following day.

What can the ultrasound scan show?

Ultrasound scanning uses sound waves which bounce back off structures in the eye and build up a picture of what is inside the eye, even when light cannot penetrate.

The scan is often used to check inside the eye if it is not possible to see directly, for example if the view is blocked by dense cataract, blood or other opacities.

Usually this is to make sure the back of the eye is healthy and, for example, the retina is not detached.

The scan can help to diagnose and measure swellings under the retina or in the optic nerve head at the back of the eye.

Scanning the front part of the eye can help diagnose some glaucoma-related conditions or check for lumps or cysts on the iris.

Cysts or swellings in the eye can be re-scanned after a few months to make sure they are not enlarging.