A 36-year-old member asked:
What is the device that looks like a pencil used to test for glaucoma?
1 doctor answer • 2 doctors weighed in
Ophthalmology 26 years experience
Tonopen: The tonopen is a device that looks like a big pencil. It measures the pressure in the eye similar to standard applanation though not as accurate.
4.8k viewsReviewed >2 years ago
Last updated Oct 25, 2013
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