Ultrasonic eye diagnosis: what it is and how it works
Ultrasonic eye diagnosis, also called ocular ultrasound or an eye ultrasound scan, uses high-frequency sound waves to produce images and measurements of the inside of the eye and the tissue behind it. A small probe sends out sound that is too high-pitched to hear. The sound bounces back from the lens, the vitreous gel, the retina, the optic nerve and the back wall of the eye, and a computer turns the echoes into a picture or a graph. The test does not use radiation and does not require dye.
It is a useful method for one reason: it works when the doctor cannot see inside the eye with a light. Cloudy tissue at the front, for example a dense cataract, blood inside the eye or a very small pupil, blocks the view of the retina, but sound passes through. This guide explains how the scan is done, what it can and cannot show, what it costs in Turkey compared with the UK, US and Germany, and how it fits with other eye tests.
A-scan and B-scan: what is the difference?
Two main types of ultrasound are used on the eye. An A-scan (amplitude scan) sends a single line of sound through the eye and records the distance between structures. It is chiefly used to measure the length of the eye, which is needed to calculate the power of an artificial lens before cataract surgery. A B-scan (brightness scan) sweeps through the eye and builds a two-dimensional picture, a slice, of the interior. It shows the shape and position of things, such as a detached retina or a growth. Some hospitals also use high-frequency ultrasound biomicroscopy, which gives a detailed image of the front of the eye, including the angle where fluid drains.
Often both are done in one visit. The doctor decides which is needed from your symptoms and what the earlier examination could and could not show.
When is ultrasonic eye diagnosis needed?
- Before cataract surgery: to measure eye length for lens power, and to check the retina behind a dense cataract that blocks the view.
- After bleeding in the eye: a vitreous haemorrhage can hide the retina, and the B-scan helps to see if the retina is still attached.
- Suspected retinal detachment: the scan can show a membrane lifting from the back of the eye when the retina cannot be seen directly.
- Lumps and growths: to measure the size, shape and internal pattern of a growth in or behind the eye, usually alongside other tests.
- After an injury: to look for a foreign object, bleeding or damage, though ultrasound is used with care when the eye wall may be open.
- Unexplained vision loss or a swollen optic nerve: to look at the optic nerve and the tissue behind the eye.
It is a diagnostic test, so it does not treat anything. The result tells the surgeon what to do next, for example whether surgery is urgent. If you have sudden flashes, a shower of floaters or a curtain across your vision, that is an emergency and needs a same-day eye examination at home, not a planned trip.
What does ultrasonic eye diagnosis show, and what are its limits?
Ultrasound is strong at showing the shape and position of structures and at measuring distances to a fraction of a millimetre in an A-scan. Professional bodies such as the Royal College of Ophthalmologists and the American Academy of Ophthalmology list it as a standard tool when the view into the eye is blocked and for biometry before cataract surgery. Its limits are equally important. It does not show the fine layers of the retina in the detail that optical coherence tomography (OCT) does, so it cannot replace OCT for macular disease; see our guide to OCT eye scan. It cannot show colour, and the picture depends on the skill of the operator, because the probe has to be aimed correctly. A normal scan does not exclude all disease, and an abnormal one is rarely a diagnosis on its own; it is interpreted together with an examination.
What happens during the test, and how should you prepare?
You do not normally need to fast or stop your medicines. Wear no eye make-up if the scan is done through the closed lid, and bring your glasses, a list of medicines and any earlier reports or scans.
- A-scan: drops numb the surface of the eye and a small probe touches the cornea briefly. The scan takes a few minutes per eye. Contact scans for lens measurement can be replaced by optical biometry if the lens is clear enough.
- B-scan: you lie or sit back with your eyes closed. A gel is spread on the closed eyelid and the probe is moved gently across it while you are asked to look in different directions. It takes about 5 to 15 minutes.
There is no pain. You may feel slight pressure from the probe, and the gel is cool. Because the surface of the eye may be numbed, avoid rubbing your eyes for about half an hour afterwards. You can usually drive and return to normal activity straight away unless drops to widen the pupil were also used, in which case your vision is blurred for a few hours.
Ultrasonic eye diagnosis cost in Turkey compared with the UK, US and Germany
These are approximate ranges for a single scan of one or both eyes with a specialist report, not hospital quotes. The price depends on whether you have an A-scan, a B-scan or both, whether it is part of a wider consultation, and whether a detailed written report is included.
| Country | Approximate cost range |
|---|---|
| Turkey | €40 – €180 |
| United Kingdom | €120 – €400 |
| United States | €200 – €800 |
| Germany | €70 – €300 |
A scan is rarely bought alone. It is usually part of a consultation or a pre-operative work-up, so ask what the price includes: the ophthalmologist's examination, both eyes, written results in English and a copy of the images. In many countries national insurance covers it when a doctor requests it, which is why private prices matter mostly to people who pay privately.
Ultrasound, OCT or other eye scans: which test answers which question?
No single test shows everything. The right one depends on what the doctor needs to see. For measuring the eye before cataract surgery, ultrasound and optical biometry are alternatives. For the layers of the retina and macula, OCT is the usual choice. For the cornea, topography is used. Our overview of eye diagnostics in Turkey lists the main tests.
| Test | Best suited to | Typical limits |
|---|---|---|
| Ultrasound (A-scan, B-scan) | Eye length, hidden retina, bleeding, growths behind a cloudy view | Less fine detail than OCT; depends on operator skill |
| OCT | Macula, retinal layers, optic nerve | Needs a clear view; poor image through dense cataract or blood |
| Direct examination with a slit lamp or ophthalmoscope | Front of the eye, retina when the view is clear | Cannot see through opacities |
It is also used in children with eye misalignment to rule out other causes before surgery; see strabismus surgery.
Is ultrasonic eye diagnosis safe, and what are the risks?
Diagnostic ultrasound has been used for decades and does not involve ionising radiation. The main risks are small. A contact A-scan can scratch the surface of the cornea, causing irritation that usually heals in a day or two, and the contact probe must be cleaned properly to avoid spreading infection. Gel in the eye can sting. In a recent injury where the eye wall may be torn, the doctor avoids pressure on the eye and may choose another test. The NHS and the American Academy of Ophthalmology describe ultrasound as a safe and routine test when performed by a trained examiner. The more serious risk is a missed or delayed diagnosis, which is why the scan should always be read alongside an ophthalmologist's examination.
Can I have an ultrasonic eye diagnosis as part of a trip to Turkey?
Yes, when it is part of a planned treatment or a second opinion. The scan itself takes under an hour and does not need any recovery, so it fits easily into a stay of two to five days. It is most often combined with a consultation, other tests such as OCT and corneal measurements, and sometimes surgery. If you travel for cataract surgery, the scan results are used to choose the lens, so take earlier measurements with you and ask whether they will be repeated. If a scan reveals something urgent, the team may advise treatment or a referral on the same trip.
How to choose an eye clinic for an ultrasound scan, and red flags
Look for a clinic where an ophthalmologist, and not only a technician, reviews your result and explains it. The equipment should be modern, probes should be cleaned between patients, and you should receive a written report with images. Red flags include a scan offered with no consultation, a quote with no mention of the report, pressure to book surgery on the day with no discussion of the findings, and no copy of your results. Read how our process works and see the full range of eye treatments in Turkey.
- Which type of ultrasound is recommended for me and why?
- Will an ophthalmologist read and explain the result?
- Do I receive the images and a report in English?
- Is the scan included in a consultation or pre-operative package?
- What further tests might be needed, and are they in the quote?
Send your eye reports and any earlier scans through the free quote page and the clinic will reply with a written plan.
Hospitals with Eye Surgery in Turkey
Frequently asked questions
It is an eye test that uses high-frequency sound waves to image and measure the inside of the eye and the tissue behind it. It involves no radiation and no dye.
An A-scan measures distances, mainly the eye's length for cataract lens calculation. A B-scan creates a two-dimensional picture of the interior, showing structures such as the retina and any growths.
Approximate ranges are €40 to €180 in Turkey, against about €120 to €400 in the UK. The price depends on the scan type, consultation and report. The clinic confirms its price in writing.
No. A B-scan uses gel on the closed eyelid, and an A-scan uses numbing drops. You may feel slight pressure, but there is no pain.
A B-scan usually takes about 5 to 15 minutes and an A-scan a few minutes per eye. The full visit, including the consultation, normally lasts under an hour.
Yes, it is widely used and involves no radiation. Minor risks include brief corneal irritation from a contact probe and, in an injured eye, a need to avoid pressure, so the doctor may choose another test.
Usually not. Bring your glasses, a list of medicines and earlier reports. If drops to widen the pupil are used, your vision may be blurred for a few hours and you should not drive.
No. Ultrasound shows shape, position and distances, particularly when the view is blocked, while OCT shows the fine layers of the retina in detail. The tests answer different questions.
It measures the length of the eye to calculate the artificial lens power and checks the retina behind a dense cataract. In clear eyes, optical biometry is often used instead.
The scan itself needs no recovery, so two to five days are usually enough when combined with a consultation and other tests. A longer stay is planned only if treatment follows.