Orthokeratology (also known as OrthoK, OK, corneal reshaping, corneal refractive therapy, and vision shaping treatment) is an alternative method to correct refractive errors using custom-designed rigid lenses to temporarily modify the curvature of cornea.1,2 Modern OrthoK technology uses breathable rigid lens material and reverse geometry designs to allow faster and more effective corneal reshaping.3 Contrasting to the traditional OrthoK designs, which use a series of progressively flattening concentric curves surrounding a central base curve fitting in alignment with the central cornea, the modern reverse geometry designs for myopia correction are characterized by a central base curve, that is, fitted significantly flatter relative to the central corneal curvature and one or more surrounding steeper secondary or “reverse” curves that enable a smooth transitioning from the flat-fitting base curve to the alignment-fitting landing curve. The unique reverse geometry design significantly improves the overall centration of OrthoK lenses despite their flatter-fitting base curves, and more efficient distribution of the hydraulic pressure underneath the lenses, allowing fasters and more significant central corneal flattening.1–3 Currently, the most common clinical application of OrthoK is for the reduction of myopia through corneal flattening.