Visual and corneal changes due to orthokeratology

Purpose: The aim of this review is the evaluation of papers about orthokeratology with the focus on changes in visual perception and corneal properties during and after orthokeratology treatment.

Material and Methods: Extensive PubMed literature search between September 2021 and July 2022 and analysis and evaluation of the selected papers according to the objectives of the review.

Results: The most significant reduction in myopia occurs during the first week of orthokeratology application, with an average correction of 1.82 to 3.33 D achieved over the treatment period. During the day, there is an average regression of 0.07 to 0.37 D, depending on the time of measurement. The results show that visual performance remains stable from the first week and a visual acuity of 20/20 or better is achieved without additional correction. Higher-order aberrations, especially spherical aberrations, can influence subjective vision under low-contrast conditions. Orthokeratology leads to a reduction in central corneal epithelial thickness, while thickness increases towards the periphery, which correlates with changes in corneal topography. Looking at the biomechanics of the cornea, it is suspected that the resistance factor and hysteresis decrease.

Conclusion: Myopia can be temporarily corrected overnight with orthokeratology. The diurnal changes in various visual functions have received little attention or have been insufficiently evaluated in the existing literature. Based on the results of previous studies and the results of this paper, the driving ability of orthokeratology wearers does not appear to be reduced in relation to the minimum requirements of the German Driver’s License Directive (FeV).