An analysis of the unexplained changes in refractive error resulting from orthokeratology

Abstract

Using results published by several clinicians, the effects of keratometer measured changes in corneal curvature induced by orthokeratology upon refractive status are examined. Various spurious sources of discrepancy between the two measurements are considered. Linear regression equations of the change in refractive error versus change in keratometer reading are calculator. A computer model schematic eye was developed and utilized to test the effects of changes in various intraocular parameters upon refractive status. A hypothesis explaining the reported 2:1 ratio of change in refractive error versus change in keratometer reading is presented. Guidelines for reducing sources of error are given