see Lid eversion.
General definition in lens geometry: The distance between an extension of the BCOR (back central optic radius) and the absolute edge of the lens; when measured parallel to the optical axis, axial edge lift (AEL); when measured along the radius, radial edge lift (REL). The term is also used when the base curve of a lens is too flat with the consequence that the edge of the lens is lifting excessively so that lens alignment with the cornea is interrupted. Often the lens will ride on the lower lid margin causing varying degrees of discomfort. Edge lift does not reduce or settle with silicone hydrogel lenses and the patient should not be fitted with lenses with this appearance. If possible a steeper basecurve should be trial fitted and assessed. Alternative expressions are lens fluting or lens buckling.
The EW patient should have access to the practitioner or a representative of the practitioner at all times in case of an emergency such as CLPU or CLARE. 24-hour access is considered as mandatory for undertaking EW practice.
Increase in size of corneal endothelial cells due to structural damage of surrounding endothelial cells. The ratio of the smallest to largest cells increases from 1:5 to 1:20. The mosaic pattern of the endothelium becomes rather irregular with cells of significantly differing sizes when viewed under specular reflection. This irreversible condition is either age related (and therefore physiological) or caused by long-term hypoxia (and therefore pathological).
Originally referred to wear of contact lenses for up to six nights and seven days without lens removal.