This document specifies minimum requirements for instruments and systems that fall into the class of corneal topographers (CTs). It also specifies tests and procedures to verify that a system or instrument complies with this document and thus qualifies as a CT according to this document. It also specifies tests and procedures that allow the verification of capabilities of systems that are beyond the minimum requirements for CTs. This document defines terms that are specific to the characterization of the corneal shape so that they may be standardized throughout the field of vision care. This document is applicable to instruments, systems and methods that are intended to measure the surface shape of the cornea of the human eye. NOTE The measurements can be of the curvature of the surface in local areas, three-dimensional topographical measurements of the surface or other more global parameters used to characterize the surface. This document is not applicable to ophthalmic instruments classified as ophthalmometers.