Case vignette
53yo M w/ no PMH presents on Halloween with L sided visual loss. He was hit in the eye with a basketball a month ago but had no symptoms after. Two hours ago, he felt a curtain descend over his L eye and now only sees blurs and flashes of light. Spooky!
VA: OD 20/25, OS HM (hand motion only). BP 120/80, HR 70, RR 14, T 36, SpO2 99%
No visible injury. Pupils equal and reactive without photophobia. EOMI. Negative fluorescin stain. No hyphema or cell/flare on slit lamp.
What do you do next?
You take off your Darth Vader costume and consider a differential for painless vision loss including stroke, central retinal arterial or venous occlusion, retinal or vitreous detachment, lens detachment, vitreous hemorrhage, optic neuritis, or migraine. You realize POCUS can rapidly assess for detachment, a time critical diagnosis, and use the force to grab your ultrasound (groan).
What do you see?
Oc1 US1: serpiginous hyperechoic layer detached from choroid, involving macula (“macula-off”)
What do you do next?
You recognize a macula-off (meaning macula is affected) retinal detachment and place an emergent call to Ophthalmology. Ophtho says since the macula is off, there is low chance of recovery — but they will take the patient to the OR regardless to attempt repair.
The patient does not recover vision. Scary, indeed.
Teaching points. POCUS can assist with time sensitive ocular diagnoses such as retinal and vitreous detachment and increased intracranial pressure. Using lots of gel, instruct the patient to keep their eyes closed and "float" a linear probe over the orbit. You can also place a Tegadarm over the eye. Visualize the posterior chamber. Retinal detachments are bright (hyperechoic), wavy lines originating from the optic nerve. The macula is just lateral to the optic nerve. If the retinal detachment involves the macula (macula-off), chances of recovery are low, and Ophtho will often recommend urgent follow up outpatient. If the macula is not affected (macula-on), vision may still be preserved, and an emergent trip to the OR is indicated.
If you do not see retinal detachment, maximize your gain and have the patient look left and right. A less bright but still hyperechoic, mobile line that is not attached to the optic nerve suggests vitreous detachment. This can be accompanied by underlying retinal lesions with impending retinal detachment. An urgent (for example, next day) follow-up with Ophtho is indicated.
Please see this excellent post for more examples and discussion: http://www.aliem.com/ocular-ultrasound-retinal-detachment-posterior-vitreous-detachment/.
Ocular ultrasound can identify many additional findings, such as:
Elevated intracranial pressure (see this excellent post: https://emcrit.org/pulmcrit/pulmcrit-algorithm-diagnosing-icp-elevation-ocular-sonography/)
Lens dislocation (see this excellent post: https://www.tamingthesru.com/blog/annals-of-b-pod/quick-hit/traumatic-lens-dislocation)
Residents: Dr. Colin Prather
Retinal Detachment
October 31st, 2020