19 July 2016 Morphology, topography, and optics of the orthokeratology cornea
Author Affiliations +
J. of Biomedical Optics, 21(7), 075011 (2016). doi:10.1117/1.JBO.21.7.075011
The goal of this work was to objectively characterize the external morphology, topography, and optics of the cornea after orthokeratology (ortho-k). A number of 24 patients between the ages of 17 and 30 years (median=24  years) were fitted with Corneal Refractive Therapy® contact lenses to correct myopia between −2.00 and −5.00 diopters (D) (median=−3.41  D). A classification algorithm was applied to conduct an automatic segmentation based on the mean local curvature. As a result, three zones (optical zone, transition zone, and peripheral zone) were delimited. Topographical analysis was provided through global and zonal fit to a general ellipsoid. Ray trace on partially customized eye models provided wave aberrations and retinal image quality. Monozone topographic description of the ortho-k cornea loses accuracy when compared with zonal description. Primary (C40) and secondary (C60) spherical aberration (SA) coefficients for a 5-mm pupil increased 3.68 and 19 times, respectively, after the treatments. The OZ area showed a strong correlation with C40 (r=−0.49, p<0.05) and a very strong correlation with C60 (r=0.78, p<0.01). The OZ, as well as the TZ, areas did not correlate with baseline refraction. The increase in the eye’s positive SA after ortho-k is the major factor responsible for the decreased retinal optical quality of the unaccommodated eye.
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
Miguel Faria-Ribeiro, Rafael Navarro Belsue, Norberto López-Gil, José Manuel González-Méijome, "Morphology, topography, and optics of the orthokeratology cornea," Journal of Biomedical Optics 21(7), 075011 (19 July 2016). https://doi.org/10.1117/1.JBO.21.7.075011


Eye models



Image quality

Biomedical optics

Modulation transfer functions


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