Certified Ophthalmic Assistant Practice Exam

What tonometry technique displaces a minimal amount of fluid?

1. Gonioscopy

2. Applanation

3. Indentation

4. Rebound

The correct answer is: Applanation

The selected answer, applanation tonometry, is indeed the correct choice because this method involves flattening a small, predetermined area of the cornea to measure intraocular pressure. Applanation tonometry, particularly with the Goldmann tonometer, is designed to displace a minimal amount of fluid in the anterior chamber while measuring the pressure, making it a reliable and standardized technique for assessing intraocular pressure. Gonioscopy pertains to examining the drainage angle of the eye and does not involve tonometry or fluid displacement. Indentation tonometry measures intraocular pressure by indenting the eye with a probe, which can displace a larger volume of aqueous humor compared to applanation. Rebound tonometry assesses pressure through a small, fast-moving probe that briefly touches the cornea and can also displace more fluid than applanation.