An 20 year old female presents to the ED as a victim of assault. She complains of severe left eye pain and decreased vision after being hit in the face. On exam, you see an ecchymotic, proptotic orbit similar to the image below with a fixed dilated pupil, chemosis, and limited EOM. The patient reports she can only see light and dark out of that eye. At what IOP should you prepare to perform a lateral canthotomy?

https://www.emra.org/emresident/article/emergency-department-evaluation-...

A. 10 mm Hg

B. 20 mm Hg

C. 30 mm Hg

D. 40 mm Hg

Answer: D. This patient’s exam is highly concerning for a retrobulbar hematoma with ocular compartment syndrome which can quickly result in permanent vision loss. A lateral canthotomy is indicated at an IOP of 40 mmHg. Of note, a suspected globe rupture is a contraindication for this procedure. Along those lines, if you see a teardrop-shaped pupil or Seidel’s sign on exam, do not measure the IOP!

Review some prior EM Daily ocular trauma pearls here: https://emdaily.cooperhealth.org/content/emconf-ocular-trauma-pearls