Mechanism for Corneal Reshaping in Hyperopic Orthokeratology

Abstract

A hyperopic OK effect was established after 1 h with increased effect with longer lens wearing time. Central fenestrations did not affect the clinical outcomes, indicating that corneal compression by the lens in the para-central region as opposed to central post lens tear film suction may be the primary mechanism behind the hyperopic OK clinical effect.

High-Resolution Spectral Domain Optical Coherence Tomography Technology for the Visualization of Contact Lens to Cornea Relationships

“…16 Myopic CRT is much more commonly prescribed, particularly because of its high predictability 17,18 compared with the still developing and less predictable hyperopic treatment. 19,20 We show the hyperopic lens here because of the more complex design.…”

Central corneal iron line arising from hyperopic orthokeratology

“…The contact lens design allows central corneal zone apical clearance to allow for central corneal steepening surrounded by the para‐central ring of bearing (Figure 3). The two current theories that have been postulated include the direct moulding from the back surface of the lens mediated by hydraulic pressures generated in the post‐lens tear film 9 or an apical suction force created within the post‐lens tear film 10 . In this case, after 3.5 years of hyperopic orthokeratology, the centrally located iron lines correlate with the area of cornea undergoing the steepening affect.…”

The effect of treatment zone diameter in hyperopic orthokeratology

“…In a previous analysis, we suggested that change to corneal curvature induced by hyperopic OK lenses was due to the corneal surface being molded towards the back surface shape of the lens (Gifford and Swarbrick, 2009). This same mechanism of effect can explain the changes in CSZ and AFZ reported here.…”