Optical changes and association with axial elongation in children wearing orthokeratology lenses of different back optic zone diameter.

"Declarations The results of this study have been previously presented at the International Myopia Conference 2022. The results have been reported in the PhD thesis entitled “Variation of orthokeratology lens treatment zone (VOLTZ) study”. Ethics approval and consent to participateThis study was conducted according to the tenets of the Declaration of Helsinki, with written consent obtained and ethics approval (HSEARS20170118004) from the Human Subject Ethics Subcommittee of the School of Optometry of the Hong Kong Polytechnic University. Consent for publicationNot applicable. Competing interestsR. Kojima is a clinical research and development director for Precision Technology Services (Vancouver, Canada), a partner in the KATT Design Group (Vancouver, Canada) and a clinical advisor to Medmont International Pty (Nunawading, Australia). Other authors have no proprietary interest in any of the products mentioned. Competing interests R. Kojima is a clinical research and development director for Precision Technology Services (Vancouver, Canada), a partner in the KATT Design Group (Vancouver, Canada) and a clinical advisor to Medmont International Pty (Nunawading, Australia). Other authors have no proprietary interest in any of the products mentioned."

"Funding B. Guo is supported by the Research Residency Scheme of the Hong Kong Polytechnic University."

"Trial registration : ClinicalTrial.gov, NCT03191942. Registered 19 June 2017, https://clinicaltrials.gov/ct2/show/NCT03191942 ."