ABSTRACT
This chapter discusses the background of the testing of applanation tonometry with clinical applications. It provides a list of equipment required for this testing. The chapter presents the instructions on the techniques of clinical examinations and methods of undertaking practical procedures by using slit-lamp biomicroscope with Goldmann tonometer and Perkins tonometer. A bullet-pointed, step-by-step walk-through of the key steps for the skill, with pearls, are also presented. Assessment of the pressure inside a fluid-filled sphere may be made by measuring the force required to flatten a part of its surface, when the thickness and rigidity of the surface is known. This is the basis of applanation tonometry, in which the plane anterior surface of a split prism of known diameter is used to flatten the surface of the cornea. The Imbert–Fick principle is the mathematical basis for the technique of applanation tonometry and makes several assumptions about the cornea that are known to be false.
