What is the term for the tonometry technique that displaces a minimal amount of fluid?

The term for the tonometry technique that displaces a minimal amount of fluid is applanation. This technique measures intraocular pressure by flattening a small area of the cornea. In doing so, it utilizes a small amount of force to achieve this flattening, which allows for an accurate measurement of pressure while minimizing fluid displacement.

In contrast, the indentation technique involves indenting the cornea into the eye and tends to displace more fluid than applanation, which is why it is not the correct answer. The elevation option refers to techniques that might consider changes from a baseline position but does not specifically relate to fluid displacement in tonometry. Lastly, fixation describes the method of maintaining a steady gaze during the measurement process rather than being a tonometric technique itself. Thus, applanation is the recognized method in clinical practice that focuses on minimal displacement, making it the appropriate answer.