Ocular Ultrasound (POCUS)

What it does

Ocular Ultrasound (POCUS) reads the eye scans that emergency physicians record through the closed eyelid. Two questions bring a patient to this scan: sudden painless loss of vision, where the posterior segment must be checked for retinal detachment or vitreous haemorrhage, and suspected raised intracranial pressure, where the optic nerve sheath behind the globe is measured.

The run reads both eyes. For the posterior segment it uses the clips taken while the patient moves the eye, because the way a membrane or an opacity moves separates the three main causes of a mobile echo in the vitreous: retinal detachment, posterior vitreous detachment and vitreous haemorrhage. For the optic nerve it measures the sheath diameter 3 mm behind the globe in two planes per eye and raises a flag when the measurement suggests raised intracranial pressure.

Intended use

Decision support for the emergency or critical-care physician deciding how urgently to involve ophthalmology or neurosurgery, and a structured record of a bedside scan that is otherwise rarely documented. The result shows the frames and calipers it relied on so the reader can check them.

Who it is for

Emergency physicians, intensivists, neurocritical-care teams, ophthalmologists receiving referrals, and POCUS educators teaching ocular scanning. Developers add the run to handheld-ultrasound apps and emergency documentation.

Accepted input

• Globe clips: B-mode cine of each eye, transverse and sagittal, as DICOM Ultrasound Multi-frame objects or MP4/MOV exports.
• Kinetic clips: cine recorded while the patient looks from side to side, for the posterior-segment read.
• Stills: transverse and sagittal stills of each optic nerve are accepted for the diameter measurement.

Requirements

Requirement	Why
Both eyes scanned	Each eye is read and reported separately
Transverse and sagittal plane of each optic nerve	The sheath diameter is measured in two planes per eye
Optic nerve shown in its long axis behind the globe	The measurement point lies 3 mm behind the globe on that axis
Eye-movement clip for the posterior segment	Detachment and vitreous disease are distinguished by how they move
Calibrated depth (SequenceOfUltrasoundRegions or a readable depth scale)	The sheath diameter is a millimetre value; without a scale, only the posterior-segment read is returned

Handheld clips are common for this scan. The result names the source of the scale used for every diameter.

Optional context

Age and the clinical question (sudden vision loss, head injury, suspected raised intracranial pressure) go in clinical_context.

The result

One JSON result in two sections with findings and measurements for each eye. The sheath diameter carries both plane values and the frames they were taken on, with calipers drawn as overlays.

Section	Content
Optic nerve sheath diameter	ONSD 3 mm behind the globe in two planes per eye, with a raised-ICP flag
Retinal detachment	Retinal detachment, posterior vitreous detachment or vitreous haemorrhage, with the supporting eye-movement frames
Draft report	Opt-in (options.report): an English narrative that interprets the result for the reader (findings, impression, limitations); every number is checked against the findings

Standards

• DICOM: SR Measurement Report TID 1500 for the diameters; GSPS calipers on the source frames; MP4 overlays of the kinetic clips; Encapsulated PDF.
• Terminology: SNOMED CT for the posterior-segment findings and laterality.

Reading notes

Optic nerve sheath diameter is a non-invasive sign of raised intracranial pressure, not a pressure value; the flag prompts further assessment. A posterior-segment finding is reported per eye with the clip that shows it moving.

Related models

• us/fast and us/lung read the other emergency point-of-care protocols.