Ocular ultrasound can be used to assess intracranial pressure in patients with suspected increases. Elevations in ICP can be seen as dilation of the optic nerve by ultrasound. The optic nerve sheath is visualized in the retrobulbar space and measured at 3mm behind the globe with the sides parallel (to prevent an artificial increase in size). A width of > 5mm has a pooled sensitivity of 90% and specificity of 85% for detecting an ICP > 20mmHg in trauma patients with head injuries. A common mnemonic for this is to think of a typical flashcard being 3x5 (3mm posterior assessing for an optic nerve >5mm)

Retinal detachments are often described with the classic “curtain drop” symptoms. Bedside ultrasound has been shown to have a sensitivity of 97% and specificity of 92% when performed by emergency physicians and can be used as an adjunct to the clinical assessment of retinal detachment. When detached, the thin retina is visible within the vitreous as a serpentine, echogenic structure attached to the posterior wall of the globe. The retina remains fixed to the choroid, which helps distinguish it from other vitreous hemorrhages or detachments. The snake-like motion can be enhanced by asking the patient to look side to side while scanning the eye. Complete tears may be attached at only the optic nerve and ora serrata, producing a V-shape within the globe.