Contact lenses in myopia reduction - from orthofocus to accelerated orthokeratology

Orthokeratology has been used to provide temporary reduction of myopia since the 1950s and in recent years the development of new lens designs, materials and advanced instrumentation for corneal modelling has resulted in a resurgence in interest in this procedure. In particular, the reverse geometry design has allowed greater myopia reduction. Materials with high oxygen permeability have improved the corneal response to rigid lenses and in orthokeratology they allow overnight retainer lens wear. Corneal modelling systems allow the orthokeratology changes to be monitored and measured, and have increased our understanding of the technique. This paper summarises previous published work in this area and identifies the uncertainties which still remain.