[Orthokeratology - a Perfect Vision Overnight - An Update and Overview].

Orthokeratology offers the unique possibility of correcting myopia: a special reverse geometry contact lens used exclusively during sleeping hours at nighttime. The authors give a comprehensive overview about the evolving technique, including the careful selection of patients, and practical contact lens fitting. They explain a series of daily life situations and point out dos and don'ts. Limitations of orthokeratology are highlighted with regard to refraction errors and anatomical conditions. Early regression and glare due to corneal aberrations are common negative side effects. Critical complications like bacterial keratitis, ocular surface disorders, and morphologic changes through corneal molding as corneal hypoesthesia and ferritin deposits are considered. Emerging applications are discussed: correction of presbyopia, corneal crosslinking to stabilize the ortho-k effect, myopia control in children, topographically controlled and individualized contact lens geometries using advanced contact lens materials. Legal regulations concerning the driving permission are outlined. Nevertheless, orthokeratology seems to be a well-established niche technology predominantly useful in young, healthy, and active myopic patients. The fitting and care of this refractive tool is demanding and costly. However, these lenses fill the gap between every day conventional contact lens and surgical refractive methods. Another growing application of high interest is myopia control in children.