Epithelial, Stromal, and Corneal Pachymetry Changes during Orthokeratology

Abstract

Refractive changes during orthokeratology treatment are mainly induced by changes in epithelial thickness profile, while stromal changes may also contribute to a small extent.

A Meta-analysis of Central Corneal Thickness Changes With Overnight Orthokeratology

“…Zhong et al 30 found central stromal thickness increased significantly after 8 hr of OK lens wear. Reinstein et al 25 also found central stromal thickening in patients with mild myopia, but they demonstrated that the magnitude of the stromal thickening was less than one-third of the magnitude of the epithelial reduction. In this case, epithelial thinning is also responsible for the total reduction of CCT.…”

Decrease in intraocular pressure following orthokeratology measured with a noncontact tonometer

“…We have now shown that overnight orthokeratology also results in a decrease in IOP as measured with an NCT, most likely because of the associated decrease in CCT. In general, the decrease in CCT associated with orthokeratology is 10-20 lm [10,[13][14][15][16][17], which is smaller than the changes induced by LASIK (80-100 lm) [21][22][23]. One view is that the refractive changes induced by overnight orthokeratology are predominantly attributable to the thinning of the corneal epithelium [13], which may not affect corneal rigidity.…”

“…It also results in a decrease in corneal thickness and increase in the flattening of corneal curvature [10,[13][14][15][16][17] and might therefore be expected to lead to a decrease in NCT measurements of IOP.…”

Automatic Segmentation of the Central Epithelium Imaged With Three Optical Coherence Tomography Devices

“…6,7,27 Optical coherence tomography has been found to be a reliable device for the measurement of the CT and ET in various conditions. 6,9,[28][29][30][31] Commercial OCT devices, such as Visante, include automatic software and have been used to measure CT. 18,19,28 The algorithm incorporated in the Visante for processing the CT map did not seem to be accessible by end users.…”