Cone prism: principles of optical design and linear measurement of the applanation diameter or area of the cornea

摘要

The cone prism introduced is mainly used in applanation tonometers to act as an applanation prism for linear measurement of the applanation diameter or the applanation area of the cornea. Its principles of optical design and linear measurement are expounded in detail. The measuring body, which comprises the cone prism and other optical and electronic parts, is also briefly introduced.