Ocular ultrasound and point-of-care scanning
- Examination
When blood or cataract hides the retina, ultrasound through the closed lid shows detachment, bleeding, a dislocated lens or a foreign body.
See it in 3D: Vitreous · Retina · Lens · Optic nerve
What it is
Ocular ultrasound (B-scan) images the inside of the eye through the closed eyelid. Ophthalmologists use it when the view of the fundus is blocked. In the emergency department, point-of-care ultrasound with a linear probe can identify retinal detachment, vitreous haemorrhage, posterior vitreous detachment, lens dislocation, an intraocular foreign body and retrobulbar haemorrhage, and measure the optic nerve sheath diameter as a sign of raised intracranial pressure.
Normal values and scales
- Retinal detachment: a bright membrane that stays tethered to the optic disc and moves little.
- Posterior vitreous detachment and vitreous haemorrhage: fine, mobile echoes that swirl with eye movement and are not tethered to the disc.
- A wide optic nerve sheath (in adults roughly over 5 mm) suggests raised intracranial pressure.
- A dislocated lens appears in the vitreous cavity; a metallic foreign body gives a bright echo with a shadow behind.
How it is done
- Ask the patient to close the eyes; cover the lid with a thick layer of gel or a protective film.
- Rest the hand on the patient's face and place the linear probe on the gel without pressing on the eye.
- Scan in transverse and longitudinal planes, sweeping through the globe.
- Ask the patient to move the eye from side to side to see whether structures move (dynamic exam).
- Measure the optic nerve sheath about 3 mm behind the globe if raised intracranial pressure is a question.
How to interpret it
- Ultrasound is avoided or done with no pressure at all when an open globe is suspected; CT is preferred.
- A normal ultrasound does not exclude a small peripheral retinal tear.
- The optic nerve sheath measurement supports, but does not replace, imaging of the brain.
Next step / Initial management
- Membrane tethered to the disc: same-day ophthalmology for retinal detachment.
- Vitreous haemorrhage: same-day ophthalmology to exclude a retinal tear or detachment behind it.
- Wide optic nerve sheath with headache or reduced consciousness: urgent brain imaging.
- Suspected intraocular foreign body: CT of the orbits and emergency referral.
Test yourself
Think of the answer, then tap the question to see it.
How is retinal detachment told apart from vitreous detachment on ultrasound?
A retinal detachment stays tethered to the optic disc and moves little; vitreous detachment and haemorrhage move freely and are not attached to the disc.
When should ocular ultrasound be avoided?
When an open globe is suspected, because pressure on the eye can worsen the injury; CT is used instead.
What does a wide optic nerve sheath suggest?
Raised intracranial pressure.
Connections
See it in 3D4
The structures of Durgical's 3D anatomy where it is found.
Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.
Sources: Point-of-Care Ocular Ultrasound (StatPearls Publishing (NCBI Bookshelf), 2026); Retinal Detachment (StatPearls Publishing (NCBI Bookshelf), 2024).
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Representative model, for educational purposes only.