B-scan ultrasound is an imaging test that uses high-frequency sound waves to produce cross-sectional pictures of the eye and orbit. It is especially useful when the view of the retina is obscured by media opacities.
Technique
An ultrasound probe is placed on the closed eyelid or on the anaesthetised eye surface with a coupling gel. The probe sends and receives sound waves, which are converted into real-time images showing the shape and position of internal structures.
- Helpful when cataract, vitreous haemorrhage, or corneal opacity prevents fundus view
- Allows assessment of retinal detachment, tumours, and foreign bodies
- Can evaluate orbital masses and extraocular muscles
- Non-invasive and generally well tolerated
Applications
B-scan ultrasound assists in diagnosing and monitoring many posterior segment and orbital diseases. It also provides measurements and information that aid surgical planning.
- Used pre-operatively when retinal status is uncertain
- Enables follow-up of tumour size or vitreous changes
- Findings are interpreted alongside clinical examination and other imaging
- Portable systems allow use in clinic or theatre settings
