Review and classification of corneal topographers

Corneal topography has, due to developments in refractive surgery and contact lens fitting, become a widely used diagnostic tool. Many types of topographers have been introduced, but there is some confusion on classification and subsequent principal possibilities of the various devices offered to the practitioner. The purpose of the study reported here was to make an inventory of developed devices, analyse the basic principles and create a classification based on optical principles. A literature search was done using Medline, the IBM Patent Server, and references found in articles and patents. This search resulted in a variety of descriptions that could be classified into 12 groups according to their use of light source and light-matter interaction of which four groups have representatives on the commercial market. This classification can be used by researchers and practitioners to gain insight into the possibilities of a given device in relation to the desired application.