- US has been well established in the ophtho literature but new advent to ED practice
- Acute/Subacute vision changes or loss
- Symptoms of increased ICP
- Suspect FB or globe rupture
- Trauma (assess for reactive pupils)
- Patient preparation
- Apply large transparent film dressing (such as Tegaderm) over the closed eye taking care not to create air bubbles between the film and skin surface
- Deposit a copious amount of ultrasound gel to the film
- Select probe
- Linear probe
- Probe should be applied to the gel without creating significant pressure on the globe itself (especially in situations of suspected globe rupture)
- The round structure of the globe should be easily identified with the lens in the anterior section
- Gain should be increased significantly to the point where echos are generating within the vitreous humor
- If needed, measurements of the optic nerve can be taken as still image
- Measure optic nerve 3mm posterior to the globe/papilla, from inner wall to inner wall
- Normal is <5mm
- U/S has a sensitivity of 95.6% and specificity of 92.3% for increased ICP
- Only perform if you can ensure that you do not put pressure on the globe
- Decrease in size of globe
- Anterior chamber collapse
- Vitreous hemorrhage
- Buckling of the sclera
Intraocular foreign body
- Bright, echogenic acoustic profile with associated shadowing or reverberation
- Echogenic undulating membrane in the posterior globe, protruding into the vitreous
- Evaluate with patient moving eye left/right
- SN 97-100% and SP 83-100%
- Retinal vs Vitreous Detachment Video (4 mins)
- May be difficult to distinguish from a retinal detachment
- May have a V-shaped appearance
- Vitreous filled with multiple large echoes
- Increasing the gain is helpful for detecting acute hemorrhages
- Biconvex or round hyperechoic structure (lens) is displaced from its normal position.
- With eye movement it may appear to move independently of surrounding structures.
- Ciliary bodies
- Vitreous chamber
- Optic nerve
Pearls and Pitfalls
- Use copious amount of gel to prevent the need for applying excessive pressure
- A high gain is generally required in order to see vitreous and retinal pathology
- Many findings are more apparent with active eye movement
A bedside ultrasound was conducted to assess for signs of retinal detachment or vitreous hemorrhage with clinical indications of left/right sided vision changes. The anterior chamber, lens, and posterior chamber of the left/right eye was identified during active movement. There was no evidence of retinal detachment or vitreous hemorrhage found. There was no sonographic evidence of retinal detachment or vitreous hemorrhage.
A bedside ultrasound was conducted to assess for signs of retinal detachment or vitreous hemorrhage with clinical indications of left/right sided vision changes. The anterior chamber, lens, and posterior chamber of the left/right eye was identified during active movement. There was a hyperechoic flap located in the anterior chamber/swirling debris in the posterior chamber. There was sonographic evidence of retinal detachment/vitreous hemorrhage.
- Blaivas M, Theodoro D, Sierzenski PR. Elevated intracranial pressure detected by bedside emergency ultrasonography of the optic nerve sheath. Acad Emerg Med. 2003 Apr;10(4):376-81.
- PulmCrit: Algorithm for diagnosing ICP elevation with ocular sonography https://emcrit.org/pulmcrit/pulmcrit-algorithm-diagnosing-icp-elevation-ocular-sonography/
- Ohle R, McIsaac SM, Woo MY, et al. Sonography of the Optic Nerve Sheath Diameter for Detection of Raised Intracranial Pressure Compared to Computed Tomography: A Systematic Review and Meta-analysis. J Ultrasound Med. 2015; 34(7):1285-1294.
- Vrablik, ME, et al. The Diagnostic Accuracy of Bedside Ocular Ultrasonography for the Diagnosis of Retinal Detachment: A Systematic Review and Meta-analysis. Annals of Emergency Medicine. 2015; 65(2):199–203.e1.