Ortho-k lenses for kids: do they work, and are they safe?

Key takeaways

Ortho-k lenses are rigid lenses worn while a child sleeps. They temporarily flatten the cornea so distance looks clear by day without glasses, and the effect lasts only while they are worn.
On average they slow the growth of the eye but do not stop it. A Hong Kong trial of children aged 6 to 10 found about 43% slower growth over two years, and Cochrane rates the one-year effect as moderate certainty.
The main risk is a corneal infection that can scar the eye and threaten sight. One practitioner survey estimated 13.9 serious infections per 10,000 years of wear in children, from only two cases.
No water of any kind may touch the lens or its case. A red, painful or light-sensitive eye means the lens comes out and the child is seen the same day.
Stopping brings the prescription back and can let eye growth catch up, and ortho-k needs more visits than glasses. It suits a child who can do the routine with a parent beside them.

Your child's power has gone up again, and someone has mentioned a lens that is worn only in sleep. Can kids wear ortho-k lenses, and are they safe? The idea is easy to like: no glasses by day, and a treatment that works while the house sleeps. It deserves a plain account of what the lens does, what the trials show and what the risk is. This page names no provider and quotes no price. Overnight lenses are called orthokeratology, or ortho-k, and in Malay they are also called kanta malam, night lenses.

What are overnight lenses (ortho-k), and how do they work?

They are rigid contact lenses worn while a child sleeps, and they temporarily flatten the centre of the cornea, the clear front window of the eye. In the morning the lens comes out, the reshaped cornea does the job glasses would do, and distance looks clear for the day. The American Academy of Ophthalmology (AAO) says the effect lasts only while the lenses are worn: stop, and the cornea slowly goes back to its normal shape and the short-sightedness returns.

Each lens is designed for one child's eye. In a 2025 study of children in Kuala Lumpur, the starting lens was worked out from a map of the cornea's shape and a measurement taken with drops that relax the focusing muscle. Why a reshaped cornea slows the growth of the eye is not fully settled. A 2017 review says the main idea is that it changes how light falls at the edge of the retina. Because the lens changes the prescription overnight, trials follow the length of the eye instead of the power.

Does ortho-k really slow short-sightedness in children?

On average, yes. It slows the climb and does not stop it. In the Hong Kong trial that randomised 102 children aged 6 to 10, the eye grew 0.36 mm over two years with ortho-k and 0.63 mm with ordinary glasses, about 43% slower. Seventy-eight children finished, and five stopped the lenses because of adverse events.

The AAO's 2019 review of 13 studies found much the same: about half the growth over two years, roughly 0.3 mm against 0.6 mm, or about half a dioptre of prescription. It concluded that ortho-k may be effective, possibly more so when started at 6 to 8. One AAO patient page, on orthokeratology in general, still says there is no firm evidence that ortho-k slows myopia in children; the Academy's 2019 review of the trials is the fuller account. A report of a 2015 World Health Organization and Brien Holden Vision Institute meeting put it in one line: ortho-k can slow myopia, but overnight wear is associated with risks.

How sure is that? The 2025 Cochrane review rates the one-year result, 0.18 mm less eye growth than the 0.33 mm in untreated children, as moderate certainty, the firmest of the lens results. Moderate is not firm. Most trials in the review were in Asia, and there is less evidence beyond two years. A Japanese study of 43 children over five years found 0.99 mm of growth with ortho-k against 1.41 mm with glasses, but the yearly gap was significant only in the first three years, and the children chose their own group. A 12-month study of 70 children in Kuala Lumpur also found less eye growth with the lenses, but parents picked the group and a lens manufacturer funded it, so it supports the picture without settling it.

Is ortho-k safe for a child? How big is the infection risk?

The main risk is an infection of the cornea, called microbial keratitis. It is uncommon, and it can scar the cornea and threaten sight. The AAO says ortho-k is associated with an increased risk of infection and calls this especially concerning in children and adolescents, who may be less able than adults to keep up good hand and lens hygiene.

Two kinds of numbers help. A practitioner survey covered 677 children and 1,435 years of lens wear and found two serious infections, an estimated 13.9 per 10,000 years of wear. That is roughly one child in 700 for each year of wear, but with only two cases the range is wide, from about 1 in 6,000 to about 1 in 200. Neither child lost vision, and the authors found the risk similar to other overnight lenses.

The other kind looks at infections that did happen. A review of 173 infected eyes in published reports, average age 15, found that Pseudomonas bacteria and Acanthamoeba were the commonest causes. Most infections left corneal scars and almost one eye in ten needed surgery. Case reports give no count of the children who wore lenses without trouble, so they show what an infection can do, not how often it happens.

In the Kuala Lumpur study the authors called the complications minor, though one of 45 ortho-k children had a contact lens peripheral ulcer. Forty-five children are far too few to measure a risk of about one in 700 a year, so a quiet year in a small study is not reassurance.

What does the nightly routine involve, and what if the eye is red?

Clean hands, fresh lens solution rather than topped-up old solution, a case replaced at least every three months, and no water of any kind on the lens or the case. The US Food and Drug Administration is plain about water: tap, bottled, distilled, lake or ocean. Tap and distilled water have been linked to Acanthamoeba keratitis, an infection that resists treatment. In a review of the first 50 infections in ortho-k wearers, 30% were Acanthamoeba, and the authors said tap-water rinsing should be eliminated. Poor lens care, ignoring the instructions of whoever fitted the lens, and wearing a lens despite discomfort were other risk factors.

Who does the routine? For a child of six to ten, plan on a parent being there every night, and contact lenses for children and teens covers the same habits for daytime lenses.

If the eye is red, painful, watery, blurred or sore in light, take the lens out and do not put it back. The FDA's advice is to remove the lens immediately and contact an eye care professional right away. In practice that means being seen the same day, not waiting to see whether it settles. When a child's eye hurts and when to go today sets out what a same-day check involves.

Which children may ortho-k suit, and who should wait?

A child who is old enough to handle a lens with a parent beside them, with low to moderate short-sightedness and little astigmatism, whose family can keep every follow-up visit. The trials set limits. The Hong Kong trial took children aged 6 to 10 with myopia between 0.50 and 4.00 dioptres and astigmatism of no more than 1.25. The Kuala Lumpur study took 0.75 to 4.00 and astigmatism up to 1.50. The College of Optometrists in the UK says a child must be old enough to look after the lenses carefully.

A child with a higher prescription or more astigmatism than the trials allowed is outside what was tested. Whether a particular cornea suits is decided by measuring it, not from a page. If the nightly routine would fall to a child alone, or visits are hard to keep, drops or glasses are a fair choice, not a lesser one.

How often are the check-ups, and what happens if we stop?

More often than for glasses, and stopping brings the short-sightedness back. The AAO says ortho-k lenses are harder to fit than regular contact lenses and need more follow-up visits. Ask for the visit schedule in writing, and what happens if a visit is missed.

When the lenses stop, two things return. The cornea goes back to its own shape, so the prescription comes back, and the growth of the eye can pick up. In a Hong Kong study of children aged 8 to 14, those who stopped ortho-k for seven months had faster eye growth, similar to when they wore glasses in the earlier trial, and it slowed again once they resumed. A 2025 review of 19 myopia-control studies found rebound after ortho-k ranged from 0.03 to 0.14 mm a year. Cochrane found limited evidence on stopping, and the AAO's review says rebound can occur after stopping or changing treatment. So stopping is a plan to make with the doctor.

How does ortho-k compare with atropine drops and myopia-control glasses?

On trial numbers it sits at the upper end of the lens results, but the comparison is indirect and the options cost a family different things. In the Cochrane review one year of treatment cut eye growth by about 0.18 mm with ortho-k (moderate certainty), 0.13 mm with defocus spectacle lenses (very low) and 0.10 mm with low-dose atropine (very low). The review warns that its networks of trials were poorly connected, so read these as separate comparisons with no treatment, not a league table.

What differs is the daily cost. Ortho-k means a lens in the eye overnight, with the corneal infection risk that comes with it. Atropine means a drop each night, and at low doses the AAO lists redness or itchiness around the eye as side effects. Glasses mean wearing them all day. The treatments can be combined: ortho-k plus low-dose atropine probably slows eye growth more than ortho-k alone, by a further 0.12 mm in a year, at moderate certainty. The guide to myopia control in Malaysia sets out the options, slowing myopia down and atropine drops for myopia give the numbers, and ten questions to ask before you pay is a checklist for any quote.

The question to take to an appointment is not whether ortho-k works. It is whether this child, this family and this routine are a safe fit.

Take the lens out and be seen the same day if…

The eye is red, painful, watery, blurred or sore in light, with a lens in or just after taking it out.
A white spot shows on the clear front of the eye.
The symptoms above follow any contact between the lens or its case and tap, bottled or other water.

Common questions

Can kids wear ortho-k lenses, and from what age?

Some can, and there is no single age. The Hong Kong trial enrolled children aged 6 to 10, and the American Academy of Ophthalmology's review says the effect may be larger when treatment starts at 6 to 8. What matters more is whether the child, with a parent beside them, can handle a lens cleanly every night and keep every follow-up visit. Whether a particular cornea suits is decided by measuring it.

Are ortho-k lenses safe for kids?

They carry a small but real risk of corneal infection, which can scar the eye and threaten sight. One practitioner survey estimated 13.9 serious infections per 10,000 years of wear in children, from two cases and with a wide range. The AAO says the risk is especially concerning in children because of hygiene. Safety rests on the nightly routine, a parent watching it, and every follow-up visit.

What are the side effects of ortho-k lenses?

Infection is the serious one. Milder problems are reported too. In a Kuala Lumpur questionnaire of 45 wearers, fewer than 10% reported trouble falling asleep, itching, burning or dry eyes, or a feeling of something in the eye after the lens went in. In the 12-month Kuala Lumpur study of 45 ortho-k children there were 5 styes, 2 cases of conjunctivitis, 1 foreign body sensation and 1 contact lens peripheral ulcer, not significantly different from the 25 children in glasses.

Can ortho-k reverse short-sightedness?

No. It reshapes the cornea temporarily and, on average, slows the growth of the eye. The AAO says that once the lenses are stopped the cornea slowly goes back to its normal shape and myopia comes back. Be wary of anyone who promises more than slowing.

What happens if my child stops wearing ortho-k?

The cornea returns to its own shape, so the prescription returns and glasses are needed again. In one Hong Kong study, children who stopped ortho-k for seven months had faster eye growth, and it slowed again when they resumed. Stopping should be planned with the doctor, who can also discuss other ways to slow myopia.

Is ortho-k better than atropine drops or myopia-control glasses?

It is not proven better, and the comparison is indirect. In the Cochrane review one year of treatment cut eye growth by about 0.18 mm with ortho-k, 0.13 mm with defocus spectacle lenses and 0.10 mm with low-dose atropine, with the ortho-k result at moderate certainty and the others at very low. Ortho-k carries the corneal infection risk that comes with any lens worn overnight. Ortho-k plus low-dose atropine probably slows growth more than ortho-k alone.

Can I buy ortho-k lenses online?

Online sales of optical devices and contact lenses on e-commerce platforms were banned by Malaysia's Medical Device Authority, announced in March 2025, which said they must be prepared and dispensed by a registered optician or optometrist. Ortho-k lenses are also made for one child's cornea, and the AAO says they are harder to fit than regular contact lenses. A lens that was never fitted to your child is not one to wear.

What should I do if my child's eye is red or sore after wearing the lens?

Take the lens out and do not put it back. The US Food and Drug Administration advises removing lenses immediately and contacting an eye care professional right away, which for a child means being seen the same day. Do not wait to see whether it settles, and do not rinse the lens or its case with water.

References

American Academy of Ophthalmology · Myopia control in children · www.aao.org
American Academy of Ophthalmology · What is orthokeratology? · www.aao.org
VanderVeen DK et al. · Use of orthokeratology for the prevention of myopic progression in children: a report by the American Academy of Ophthalmology, Ophthalmology 2019 · pubmed.ncbi.nlm.nih.gov
Cho P, Cheung SW · Retardation of myopia in Orthokeratology (ROMIO) study: a 2-year randomized clinical trial, Investigative Ophthalmology and Visual Science 2012 · pubmed.ncbi.nlm.nih.gov
Lawrenson JG et al. · Interventions for myopia control in children: a living systematic review and network meta-analysis, Cochrane Database of Systematic Reviews 2025 · pubmed.ncbi.nlm.nih.gov
Hiraoka T et al. · Long-term effect of overnight orthokeratology on axial length elongation in childhood myopia: a 5-year follow-up study, Investigative Ophthalmology and Visual Science 2012 · pubmed.ncbi.nlm.nih.gov
Low YC et al. · Impact of orthokeratology on corneal morphology, ocular health and myopia control in children: a 12-month clinical assessment in myopic children living in Kuala Lumpur, Malaysia, Clinical Optometry 2025 · pubmed.ncbi.nlm.nih.gov
Mohd-Ali B et al. · Comparison of vision-related quality of life between wearing orthokeratology lenses and spectacles in myopic children living in Kuala Lumpur, Contact Lens and Anterior Eye 2023 · pubmed.ncbi.nlm.nih.gov
Bullimore MA, Sinnott LT, Jones-Jordan LA · The risk of microbial keratitis with overnight corneal reshaping lenses, Optometry and Vision Science 2013 · pubmed.ncbi.nlm.nih.gov
Kam KW et al. · Infectious keratitis and orthokeratology lens use: a systematic review, Infection 2017 · pubmed.ncbi.nlm.nih.gov
Watt K, Swarbrick HA · Microbial keratitis in overnight orthokeratology: review of the first 50 cases, Eye and Contact Lens 2005 · pubmed.ncbi.nlm.nih.gov
US Food and Drug Administration · Contact lens risks · www.fda.gov
Centers for Disease Control and Prevention · Preventing eye infections when wearing contacts · www.cdc.gov
American Academy of Ophthalmology · Corneal ulcer (keratitis) · www.aao.org
Cho P, Cheung SW · Discontinuation of orthokeratology on eyeball elongation (DOEE), Contact Lens and Anterior Eye 2017 · pubmed.ncbi.nlm.nih.gov
Bullimore MA, Brennan NA · Efficacy in myopia control: the impact of rebound, Ophthalmic and Physiological Optics 2025 · pubmed.ncbi.nlm.nih.gov
Li X et al. · Update on orthokeratology in managing progressive myopia in children: efficacy, mechanisms, and concerns, Journal of Pediatric Ophthalmology and Strabismus 2017 · pubmed.ncbi.nlm.nih.gov
World Health Organization and Brien Holden Vision Institute · The impact of myopia and high myopia: report of the joint global scientific meeting on myopia, 2015 · myopiainstitute.org
College of Optometrists · Myopia management guidance: FAQs · www.college-optometrists.org
The Star · MDA bans online sale of optical devices, contact lenses, 25 March 2025 · www.thestar.com.my

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.

Overnight lenses (ortho-k) for children: how they slow myopia, the infection risk, and who they suit