Certified Ophthalmic Technician (COT) Practice Test 2025 - Free COT Practice Questions and Study Guide

The correct answer is applanation. This technique involves flattening a small area of the cornea to measure intraocular pressure (IOP). During applanation tonometry, a precise amount of force is applied to flatten the cornea, which correlates well with the pressure inside the eye. This method allows for the displacement of the least amount of fluid, minimizing the potential for altering the intraocular environment while providing accurate IOP readings.

Other techniques mentioned, such as pneumatic tonometry, utilize a puff of air to measure pressure, which can displace more fluid than necessary and may not provide as accurate a reading in certain situations. Digital tonometry relies on the physician’s tactile sense to estimate pressure and is more subjective. Lastly, penetration tonometry is not a standard term in tonometry and does not specifically relate to measuring IOP as applanation does. Therefore, applanation remains the most appropriate term for a technique that minimizes fluid displacement while providing reliable measurements of intraocular pressure.