Orthokeratology (ortho-k) involves using rigid, gas-permeable contact lenses worn overnight to shape the cornea and correct mild to moderate refractive errors.
A child does not need to wear the lenses during the day, but the effect is temporary, and they need to be worn regularly at night to maintain clear daytime vision.
Orthokeratology (ortho-k), when used for partial or full correction of myopia, has been shown to slow myopic progression in children by 36-56% compared to their spectacle or contact-lens-wearing peers.
(source: https://clinicaltrials.gov/ct2/show/NCT03465748)
