Ocular Ultrasound

Equipment Selection

Use of a high resolution, small footprint probe (10-15MHZ) is essential when assessing the internal structures of the globe. Good colour / power / Doppler capabilities when assessing vessels or vascularity of a structure.

Scanning Technique

Scan the patient through closed eyes.

Give the patient some tissues and explain that should they need to open their eyes, to let you know and they can use the tissues to wipe their eye.

If possible, use sterile gel. Apply a small amount of gel to the probe.

Be prepared to change frequency output of probe (or probes) to adequately assess both superficial and deeper structures.

Anterior Chamber

Reduce the depth to include the posterior aspect of the lens and zoom to fill the screen.

Use thick gel and minimal to no pressure because the anterior chamber is easily compressed. Sweep in both sagittal and transverse checking for symmetry. Look for sharp margins where the cornea meets the lateral margins of the iris & ciliary bodies.

Ensure the lens is intact, anechoic and normally located. A cataract will be seen as echogenic heterogeneity of the lens.

Document the normal anatomy and any pathology found, including measurements and vascularity if indicated.

Posterior Chamber

Increase the depth to include the entire globe and proximal optic nerve.

In transverse, ask the patient to look left and right to facilitate maximum scan range. Similarly, in sagittal, ask the patient to look up/down. Look for a smooth inner wall of uniform thickness and echogenicity. Check for homogeneity of the vitreous humour. Commonly in elderly people there will be some echogenic 'debris' within the vitreous due to degenerative changes. A vitreous haemorrhage will be seen as mobile, fibrinous, complex material possible tethered.

Whilst rare to see pathology, check that the optic nerve is unform and symmetrical in size bilaterally with no retro-occular masses.

Document the normal anatomy and any pathology found, including measurements and vascularity if indicated.

Common Pathology

• Vitreous haemorrhage

• Retinal detachment

• Choroidal detachment

• Melanoma

• Lens replacement and pathology

• Foreign body and trauma

• Drusen

• Staphyloma

Basic Hard Copy Imaging

An eye series should include the following minimum images:

• Anterior chamber - longitudinal and transverse.

• Entire globe: Longitudinal-eyes up/down

• Entire globe: Transverse-eyes left/right

• Power doppler of retina

• Macula/Fovea longitudinal and transverse

• Comparison Right V's Left