CornealreflexThe corneal reflex test (blink test) examines the reflex pathway involving cranial nerves V and VII. Classically the provider lightly touches a wisp of cotton on the patient’s cornea. This foreign body sensation should cause the patient to reflexively blink.

This maneuver always makes me a little worried about causing a corneal abrasion, especially if you are examining a very somnolent patient. You are wondering — Is there no blinking because you’re not touching the cornea hard enough? You apply harder pressure but still no blink. You repeat the test and now the patient finally blinks. That’s 3 times you’ve just scraped against the cornea.

What’s an alternative approach?

Trick of the Trade

Apply drops of sterile saline on the eye.


When a patient presents with a low GCS, you want to perform rapid neurologic exam. I’ve been seeing our neurologists do a quick simple test for corneal reflexes. Grab a pre-filled sterile saline syringe, typically used to flush IV’s, and squirt a few drops on the eye. Look for the patient to blink.

This seems much safer and definitive of a test of the corneal reflex.

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


Professor of Emerg Med at UCSF-Zuckerberg SF General. ALiEM Founder @aliemteam #PostitPearls at Bio:
Michelle Lin, MD