Orthokeratology, often called Ortho-K, is a non-surgical vision correction method that uses specially designed rigid contact lenses worn overnight to temporarily reshape your cornea while you sleep. You remove the lenses in the morning and see clearly throughout the day without glasses or daytime contacts. The effect is reversible: if you stop wearing the lenses, your cornea gradually returns to its original shape and your vision goes back to what it was before.
How Overnight Lenses Reshape Your Eye
Ortho-K lenses have a “reverse geometry” design, meaning the curves on the back of the lens are engineered to apply gentle, controlled pressure across different zones of your cornea. While you sleep, this pressure redistributes the thin outer layer of the cornea (the epithelium), compressing it slightly in the center and pushing tissue toward the mid-periphery. That central flattening is what corrects nearsightedness. The tear film between the lens and your eye acts as a hydraulic cushion, helping guide this redistribution evenly.
The reshaping happens entirely within the epithelium, which is only about five or six cell layers thick. No deeper corneal tissue is altered, which is why the effect wears off within a day or two if you skip a night. Research confirms that the degree of vision correction maps directly to how much the central epithelium thins, reinforcing that this superficial tissue shift is the primary mechanism at work.
What Ortho-K Can Correct
Ortho-K works best for mild to moderate nearsightedness. The FDA approved one major lens design for myopia up to negative 6.00 diopters, but most lens manufacturers set their practical correction range between negative 3.50 and negative 4.50 diopters. Within that range, full correction to clear daytime vision is reliably achievable. Higher prescriptions can sometimes be partially corrected, though results become less predictable.
Astigmatism correction is more limited. Most designs handle up to 1.50 diopters of with-the-rule astigmatism (the more common type, where the steeper curve runs vertically) and only about 0.75 diopters of against-the-rule astigmatism. If your astigmatism exceeds those thresholds, you may still be a candidate, but your eye care provider will need to evaluate whether a specialty toric Ortho-K design could work for your corneal shape.
The First Few Weeks
Vision improvement with Ortho-K is gradual. After the first night, most people notice some change, but it’s typically not enough for comfortable all-day vision without backup glasses. After one to two weeks of consistent nightly wear, improvements become more significant. Full, stable correction generally takes four to six weeks.
During that initial period, your eye care provider will schedule several follow-up visits to check the fit, monitor corneal health, and assess how your eyes are responding. You may need to wear disposable soft lenses or glasses during the day for the first week or two until the reshaping catches up. Once vision stabilizes, most people achieve functional 20/20 vision that lasts from morning until evening.
Slowing Myopia in Children
Beyond correcting existing nearsightedness, Ortho-K has a second major use: slowing down myopia progression in children. Childhood myopia tends to worsen year after year as the eyeball elongates. An assessment published by the American Academy of Ophthalmology found that Ortho-K reduced this axial elongation by roughly 50% over a two-year period compared to standard glasses or contacts. The effect was even stronger in children younger than 9.
The leading theory for why this works involves peripheral focus. In a nearsighted eye corrected with regular glasses, light hitting the edges of the retina focuses slightly behind it, which may signal the eye to keep growing longer. Ortho-K reshapes the cornea in a way that shifts peripheral light focus in front of the retina instead, potentially removing that growth signal. This myopia control benefit has made Ortho-K one of the most widely used interventions for children with progressing nearsightedness, alongside low-dose atropine eye drops, which work through a completely different pathway by modulating chemical receptors that regulate eye growth.
How It Compares to Other Options
The most obvious comparison is LASIK. Both aim for glasses-free vision, but they differ fundamentally. LASIK permanently reshapes deeper corneal tissue with a laser and is only performed on adults whose prescriptions have stabilized, typically after age 18 to 21. Ortho-K is temporary, reversible, and suitable for children. For adults who aren’t ready for surgery, don’t qualify, or simply prefer a non-permanent option, Ortho-K fills a gap that LASIK doesn’t cover.
For myopia control in children specifically, the main alternatives are low-dose atropine drops and specially designed multifocal soft contact lenses. Low-dose atropine has minimal side effects at lower concentrations and doesn’t require lens wear, but it doesn’t correct vision on its own, so your child still needs glasses. Ortho-K does both: it corrects current vision and slows progression simultaneously. Some practitioners combine Ortho-K with low-dose atropine for an additive effect, though this approach is still being refined.
Safety and Infection Risk
The primary safety concern with Ortho-K is corneal infection, specifically microbial keratitis, because the lenses are worn overnight when the eye is closed and oxygen supply to the cornea is reduced. A study tracking Ortho-K wearers estimated the overall incidence of microbial keratitis at 7.7 per 10,000 patient-years of wear. For children, the rate was higher at 13.9 per 10,000 patient-years, while no cases were recorded in adults during the study period. Importantly, neither infection case in the study resulted in permanent vision loss.
These rates are comparable to other types of overnight contact lens wear, not meaningfully higher. The key to keeping risk low is proper hygiene: washing hands before handling lenses, using fresh disinfecting solution every night (never topping off old solution), replacing lens cases regularly, and attending all scheduled follow-up appointments. Minor issues like corneal staining, mild erosion, and temporary dry eye are more common than infection but are generally caught early at checkups and resolve quickly.
What It Costs
Ortho-K is more expensive upfront than standard glasses or soft contacts. Initial costs, including the fitting process, the custom lenses, and the series of follow-up visits needed to dial in the prescription, generally range from $1,000 to $4,000 depending on your prescription complexity and where you live. After that, annual maintenance runs between $300 and $500 for replacement lenses, cleaning solutions, and periodic checkups.
Most vision insurance plans treat Ortho-K as a specialty service and offer limited or no coverage, though some plans with myopia management benefits for children are starting to include it. If you’re considering Ortho-K primarily for a child’s myopia control, it’s worth comparing the cumulative cost against years of progressively stronger glasses, since slowing progression now can reduce the likelihood of high myopia and its associated eye health risks later in life.
Who Is a Good Candidate
The best candidates for Ortho-K are people with mild to moderate myopia (up to about negative 4.50 diopters), low astigmatism, and healthy corneas. Children with progressing myopia are a particularly strong fit because of the dual benefit of correction and slowing progression. Adults who play sports, work in dusty or dry environments, or simply find daytime contacts uncomfortable often appreciate the freedom of lens-free days.
Ortho-K is not appropriate for people with active eye infections, significant corneal irregularities, or chronic conditions that compromise the surface of the eye. Your provider will evaluate your corneal shape, tear film quality, and overall eye health before determining whether you’re a good fit. Because the lenses are custom-made based on detailed corneal mapping, the fitting process is more involved than picking up a box of soft contacts, typically requiring multiple visits over the first month.