US researchers have recommended clinicians monitor orthokeratology (ortho-k) patients' refraction, tomography, pachymetry and corneal biomechanics until stability is achieved before considering refractive surgery. 

Writing in Eye & Contact Lens, researchers said their literature search revealed several changes associated with ortho-k use, including higher corneal staining, central corneal epithelial thinning and midperipheral thickening, increased higher-order aberrations, decreased contrast sensitivity, reduced corneal hysteresis and corneal resistance factor and alterations in the tear proteome. The majority of these parameters returned to baseline after ortho-k lens discontinuation, with timing potentially dependent on the amount of myopic correction, duration of ortho-k use and age of lens fitting, they said. 

“Despite the paucity of articles describing prior ortho-k patients undergoing corneal refractive surgery, it is evident that ortho-k use may potentially cause various corneal physiological, tomographic, and biomechanical changes in patients,” they said.