Also found in: Acronyms.
Deviation of the posterior surface of a contact lens from a sphere at a given diameter. This is produced by either the peripheral curve(s) or the edging process. Edge lift provides peripheral clearance of a rigid contact lens, which is assessed by fluorescein pattern. If the edge lift is specified axially (as an extension of the back central optic zone, measured parallel to the axis of symmetry) it is referred to as axial edge lift. If specified radially as an extension along the back optic zone radius it is referred to as radial edge lift. See optic zone diameter; back optic zone radius.