The relationship between corneal biomechanics and anterior segment parameters in the early stage of orthokeratology

Abstract

To investigate the relationship between corneal biomechanics and anterior segment parameters in the early stage of overnight orthokeratology.Twenty-three eyes from 23 subjects were involved in the study. Corneal biomechanics, including corneal hysteresis (CH) and corneal resistance factor (CRF), and parameters of the anterior segment, including corneal curvature, central corneal thickness (CCT), and corneal sublayers’ thickness, were measured at baseline and day 1 and 7 after wearing orthokeratology lens. One-way analysis of variance with repeated measures was used to compare the longitudinal changes and partial least squares linear regression was used to explore the relationship between corneal biomechanics and anterior segment parameters.At baseline, CH and CRF were positively correlated with CCT (r = 0.244, P = .008 for CH; r = 0.249, P < .001 for CRF), central stroma thickness (CST) (r = 0.241, P = .008 for CH; r = 0.244, P = .002 for CRF) and central Bowman layer thickness (CBT) (r = 0.138, P = .039 for CH; r = 0.171, P = .006 for CRF). Both CH and CRF significantly decreased from day 1 after orthokeratology. The corneal curvature and the epithelium thickness also significantly decreased, while the stromal layer thickened significantly from day 1 after orthokeratology. There was no correlation between the changes of corneal biomechanics and anterior segment parameters at day 1 and 7 after orthokeratology.While corneal biomechanics were positively correlated with CCT, CST, and CBT, the changes of CH and CRF were not correlated with the changes of corneal curvature, CCT, and corneal sublayers’ thickness in the early stage of orthokeratology in our study.

Redistribution of the corneal epithelium after overnight wear of orthokeratology contact lenses for myopia reduction

“…Some authors found that the main change in corneal thickness was in the corneal epithelium after OK lens wear [2,9,17,18]. However, there is still no internationally unified view on how the corneal epithelium is redistributed after lens wear [16,[19][20][21][22]. Lian et al [16] found central, horizontal, and vertical meridian epithelium thinning, horizontal meridian nasal temporal side paracentral epithelial thickening, and above vertical meridian paracentral epithelium thinning at 1 month of lens wear by UHR-OCT. Chen et al [19] found that the central epithelium thinned and the corneal stroma thickened at 1 day of lens wear.…”

“…However, there is still no internationally unified view on how the corneal epithelium is redistributed after lens wear [16,[19][20][21][22]. Lian et al [16] found central, horizontal, and vertical meridian epithelium thinning, horizontal meridian nasal temporal side paracentral epithelial thickening, and above vertical meridian paracentral epithelium thinning at 1 month of lens wear by UHR-OCT. Chen et al [19] found that the central epithelium thinned and the corneal stroma thickened at 1 day of lens wear. Nieto-Bona et al [20] observed that the central 2 mm corneal epithelium was thinning, while there was no obvious change in corneal stroma by confocal microscope.…”

Association between long-term orthokeratology responses and corneal biomechanics

“…After orthokeratology, the corneal epithelium is reduced 29,30 , but the corneal stroma thickens 31,32 . These changes in the morphological and histological properties of the cornea may alter its biomechanical properties 33 . The current study applied both a dynamic bidirectional corneal applanation technology (i.e.…”

Redistribution of the Corneal Epithelium After Overnight Wear of Orthokeratology Contact Lenses for Myopia Reduction

“…17]. Lian Y[10] found central, horizontal, and vertical meridian epithelium thinning, horizontal meridian nasal temporal side paracentral epithelial thickening, and above vertical meridian paracentral epithelium thinning at 1 mo of lens wear by UHR-OCT. Chen R[14] found that the central epithelium thinned and the corneal stroma thickened at 1 day of lens wear. Nieto-Bona-A[15] observed that the central 2-mm corneal epithelium was thinning, while there was no obvious change in corneal stroma by confocal microscope.…”