Indications

• Evaluation for Increased Intracranial Pressure (see Increased Intracranial Pressure, [[Increased Intracranial Pressure]])

Technique

• Measure 3 (0.3 cm) mm back from retina
• Ultrasound contrast is high at this point, allowing more reproducible measurements of ONSD
• Measure perpendicular at that point: >5 mm (0.5 cm) width of optic nerve sheath (Optic Nerve Sheath Diameter = ONSD) indicates increased ICP (>20 mm Hg)

References

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