Trick of the Trade: Check pupillary constriction with ultrasound

Posted by Michelle Lin, MD on Apr 06, 2011

In some trauma patients with head and face trauma, you will need to check their pupillary response to light. Severe periorbital and eyelid swelling, however, make this difficult. You want to minimize multiple attempts to retract the eyelids because of the risk of a ruptured globe. What’s a minimally painful and traumatic way to check for pupillary constriction?

Trick of the Trade:

Use an ultrasound with a linear transducer

Apply generous ultrasound gel on the patient’s closed eyelid.
Have the patient look straight ahead (with eyelids closed).
Gently position the transducer obliquely on the eyelid in either a sagittal or transverse plane.
Shine a light into the other eye. If the other eyelid is swollen, you can actually shine a light through a closed eyelid. The pupil can sense light through the thin upper eyelid.
Watch for pupillary constriction on the screen.

Thanks to Dr. Miss for this tip and Drs. Kornblith and Hensley for demonstrating.

Author information

Michelle Lin, MD

ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco

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Tags: Ophthalmology, Tricks of the Trade, Ultrasound