Hello. I’m Dr. Jinhag Baik, an ophthalmologist and head director of nuneHIM Eye Center on Siheung-daero in Guro-gu, Seoul.
When parents ask about orthokeratology (ortho-k, called “dream lens” in Korea), the first question is often about safety, not results. Your child sleeps in a rigid lens every night, so the worry makes sense.
Here is the short answer. Infectious (microbial) keratitis from ortho-k is uncommon, but when it happens it can leave a scar on the cornea. Studies keep pointing to the same risk factors, and they are about lens care habits more than the lens itself: water touching the lens or case, using an old case, and continuing to wear lenses when the eye hurts.
What ortho-k does, and why the AAO calls safety a concern
Ortho-k lenses are rigid, oxygen-permeable lenses worn overnight. They temporarily reshape the front of the cornea so a child can see clearly during the day. The effect wears off if the lenses are stopped, so it is a nightly routine, not a one-time treatment.
In children, the main reason to use ortho-k is to slow myopia progression. In the ROMIO randomized trial in Hong Kong (children aged 6–10), axial length grew 43% more slowly over two years with ortho-k than with single-vision glasses (0.36 mm vs 0.63 mm). The American Academy of Ophthalmology’s 2019 technology assessment concluded that ortho-k may be effective, possibly more so when started at ages 6–8, but that “safety remains a concern because of the risk of potentially blinding microbial keratitis.”
How often does keratitis happen?
- US study (Bullimore et al., 2013): 1,317 wearers, 2,599 patient-years. Two cases, both in children, neither with vision loss. Estimated incidence: 7.7 per 10,000 patient-years overall, 13.9 in children (95% CI 1.7–50.4).
- Japanese multicenter study (2024): 1,438 wearers (mean age 12.7), 7,415 patient-years. Four cases: 5.4 per 10,000 patient-years, which the authors describe as comparable to daily-wear soft lenses.
These numbers mean keratitis is rare, but not zero, and a small yearly risk adds up over years of nightly wear. They do not prove children are twice as risky as adults: there were only two cases in the US study, and the authors note it could not detect differences smaller than 50 per 10,000 patient-years.
Why water is the big one
Reviews of reported ortho-k infection cases found Pseudomonas in 38–52% and Acanthamoeba in 30–33%. Researchers repeatedly linked Acanthamoeba to rinsing lenses or cases with tap water. The US CDC notes Acanthamoeba is commonly found in tap water and other water sources, and that this infection can need a year or more of treatment. The FDA advises never exposing contact lenses to any water, including tap, bottled, or distilled water.
Habits that matter at home
Based on CDC and FDA contact lens guidance (follow the specific solution and steps you were prescribed):
- Wash hands with soap and dry them fully before touching lenses.
- Rub and rinse lenses with the prescribed solution; use fresh solution in the case every time, never topping off.
- Rinse the case with solution, not water; empty it, wipe it, and air-dry it upside down with caps off.
- Replace the case at least every three months.
- If water touches a lens, don’t put it in. Clean and disinfect it again, or call us if unsure.
- Keep backup glasses ready.
Skip the lens tonight if you notice
Eye pain, redness that doesn’t settle, light sensitivity, more tearing or discharge, or blurry vision even with glasses. The FDA advises removing lenses, not reinserting them, and bringing the lenses in their case to your eye doctor. Early diagnosis matters: the AAO report notes poorer outcomes when treatment is delayed. Tell your child that saying “my eye hurts” is always the right call.
For busy expat families near Gasan and Guro Digital Complex
Keep all lens supplies in one dry spot (not next to the bathroom sink), split morning and evening lens tasks between parents, and pack a travel pouch with case, solution, and glasses for sleepovers. Bring the lenses and case to regular check-ups so we can review them together. If you are thinking of stopping or switching treatments, talk to us first: the AAO notes myopia can rebound after discontinuation, and other options such as low-dose atropine are worth discussing.
Bottom line
Ortho-k keratitis is rare but serious. Keep water away from lenses and the case, replace the case every three months, and skip the lens and see an eye doctor when the eye hurts.
nuneHIM Eye Center | Dr. Jinhag Baik, Ophthalmologist
5F Kwanghee Bldg, 551 Siheung-daero, Guro-gu, Seoul (near Guro Digital Complex and Gasan Digital Complex stations)
www.nunehim.com | Naver booking: https://booking.naver.com/booking/13/bizes/923695
This article is for general medical information. Results and risks depend on each person’s eyes and lens care, and the decision to use ortho-k should be made after an examination by an ophthalmologist.
References: Cho & Cheung, IOVS 2012 (ROMIO); VanderVeen et al., Ophthalmology 2019 (AAO OTA); Bullimore et al., Optom Vis Sci 2013; Japanese multicenter study, Jpn J Ophthalmol 2024 (PMID 39549214); Watt & Swarbrick, Eye Contact Lens 2005 and 2007; CDC Healthy Contact Lens Wear and Care; FDA Contact Lens Risks.
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