Orthokeratology Research: Myopia Control and Safety

Orthokeratology, commonly known as Ortho-K, uses specially designed rigid contact lenses worn overnight to temporarily reshape the front surface of the eye. After the lenses are removed in the morning, many patients can see clearly during the day without glasses or contact lenses.

For children with progressive myopia, Ortho-K may also be used as part of a broader myopia-management program to help slow the rate at which the eye continues to grow.

Research consistently supports Ortho-K as an effective option for slowing axial eye growth in children. However, it does not guarantee that myopia will stop progressing completely, and the amount of benefit varies between individual children. Regular eye-health examinations and axial-length measurements remain important throughout treatment.

Ortho-K Research at a Glance

Does Ortho-K Really Control Myopia?

Myopia usually progresses when the eye grows too long from front to back. This measurement is known as the eye’s axial length.

Ortho-K temporarily changes the shape of the cornea to correct vision during the day. It also changes the way light is focused across the peripheral retina, which is thought to help reduce the stimulus for further axial eye growth.

Because Ortho-K changes the shape and prescription of the cornea, changes in spectacle prescription alone cannot reliably show whether treatment is controlling myopia. Axial length is therefore one of the most important measurements used to assess treatment response.

The International Myopia Institute recommends that myopia management include appropriate vision correction, an evidence-based intervention to slow progression, lifestyle advice and ongoing monitoring of refraction and axial length.

What Does the Current Research Show?

2025 Cochrane Living Systematic Review

Interventions for Myopia Control in Children: A Living Systematic Review and Network Meta-analysis

This comprehensive review examined the available evidence for multiple childhood myopia treatments.

The review found moderate-certainty evidence that Ortho-K reduces axial elongation compared with conventional correction. The average treatment effect was approximately 0.18 mm at one year and approximately 0.30 mm over two years.

The authors identified Ortho-K as one of the best-supported optical treatments for slowing childhood axial elongation. They also noted that more long-term research is required and that individual treatment responses vary.

2024 Pooled Analysis of Prospective Studies

A New Look at the Myopia Control Efficacy of Orthokeratology

This study combined data from three prospective Ortho-K studies involving children.

Over two years, average axial elongation was:

• 0.41 mm in children wearing Ortho-K lenses
• 0.65 mm in children wearing single-vision spectacles

This represented an average treatment effect of 0.24 mm over two years.

The study also demonstrated considerable variation between children. Approximately 40% of Ortho-K wearers showed very low axial progression, while approximately 25% continued to show relatively rapid eye growth.

This reinforces why treatment should be assessed individually using repeat axial-length measurements rather than relying only on average research results.

2025 Eleven-Year Follow-Up

Eleven Years of Orthokeratology Contact Lens Wear for Slowing Myopia Progression in Children

This long-term follow-up study compared children who had worn Ortho-K lenses with children who had used conventional single-vision correction.

After 11 years, the Ortho-K group had experienced up to 0.69 mm less axial elongation than the comparison group. A large proportion of the benefit occurred during the first two years, but the difference continued to accumulate over time.

This is the longest published follow-up comparing axial growth in Ortho-K and single-vision lens wearers. However, it should not be interpreted as a continuously randomised 11-year clinical trial, and long-term follow-up studies can be affected by participant dropout and other differences between groups.

2025 Three-Year Scandinavian Study

Myopia Control With Orthokeratology Lenses: A Three-Year Follow-Up Study Including a Cross-Over Design

This study found that the myopia-control effect of Ortho-K remained stable over three years of treatment. Similar treatment effects were observed across the ages included in the study, and no severe adverse events occurred during the study period.

Does Ortho-K Stop Myopia Completely?

No myopia-control treatment can guarantee that progression will stop completely.

Ortho-K generally reduces the rate of axial growth rather than preventing all further growth. A child may still require changes to their lens design or additional treatment if their eyes continue to grow more quickly than expected.

The response can be influenced by factors including:

• The child’s age
• Their existing level of myopia
• Family history
• Previous rate of progression
• Lens fit and treatment-zone position
• Wearing time and consistency
• Time spent outdoors
• Other individual eye and lifestyle factors

For children whose myopia continues to progress despite Ortho-K, another treatment may occasionally be recommended alongside it. This decision should be based on the child’s results, individual risks and current clinical evidence.

Why Do We Measure Axial Length?

A child may continue seeing clearly through their Ortho-K treatment while the eye is still becoming longer.

Axial-length measurement allows us to assess structural eye growth independently of the temporary corneal reshaping produced by Ortho-K lenses. It provides a more objective way to determine whether treatment is adequately slowing progression.

The International Myopia Institute considers axial length a critical measurement for myopia management and recommends monitoring treatment efficacy rather than assuming that clear daytime vision means myopia is controlled.

At Westmead Eyes, myopia-management reviews may include:

• Axial-length measurement
• Refraction and vision assessment
• Corneal topography
• Examination of the cornea and front of the eye
• Assessment of lens fit and treatment-zone position
• Review of lens condition, cleaning and handling
• Discussion of wearing time and lifestyle factors

The frequency and type of testing will depend on the child’s age, treatment response and individual risk factors.

Is Orthokeratology Safe?

Ortho-K is generally well tolerated when lenses are properly fitted, carefully maintained and regularly reviewed.

However, Ortho-K involves overnight contact-lens wear. As with all contact lenses, complications can occur. These may include:

• Corneal staining
• Temporary irritation or discomfort
• Lens binding
• Inflammatory events
• Fluctuating or reduced vision
• Halos or glare, particularly at night
• Infection of the cornea

Most complications are minor and resolve after lens wear is temporarily stopped or the treatment plan is adjusted. Microbial keratitis is uncommon but is the most serious potential complication because it can threaten vision.

What Is the Latest Estimate of Infection Risk?

2025 Multicentre Microbial Keratitis Study

Incidence of Microbial Keratitis Associated With Overnight Orthokeratology: A Multicentre Collaborative Study

This large study reviewed 1,438 Ortho-K wearers representing 7,415 patient-years of lens wear.

Four cases of microbial keratitis were identified. The estimated incidence was:

5.4 cases per 10,000 patient-years

This means serious infection was uncommon within the population studied. However, the risk was not zero, and microbial keratitis requires urgent assessment and treatment.

Infection estimates from different studies should be compared cautiously because lens-care systems, practitioner training, study populations and methods may differ.

What About Other Adverse Events?

A separate 2025 analysis combined safety data from three prospective Ortho-K studies.

Using a broad definition that included both minor and more significant findings, the researchers estimated that approximately 13% of eyes experienced an adverse event during one year of lens wear. The rate was lower when only events considered likely to be contact-lens related were included.

These findings do not mean that 13% of wearers experience serious infections. Most reported events were not microbial keratitis. The study instead highlights the importance of regular reviews so that relatively minor changes can be identified and managed early.

Reducing the Risks of Ortho-K

Successful and safe Ortho-K wear depends on correct lens handling and consistent follow-up care.

Ortho-K wearers should:

• Wash and completely dry their hands before handling lenses
• Clean and disinfect lenses using the recommended system
• Use fresh solution each time
• Never rinse or store lenses in tap water
• Avoid showering, swimming or using a spa while wearing the lenses
• Keep the lens case clean and replace it as recommended
• Avoid wearing damaged, chipped or heavily deposited lenses
• Attend scheduled eye-health and lens-fit reviews
• Stop lens wear and contact the practice promptly if symptoms develop

Contact lenses should be kept away from tap water, swimming pools, spas and shower water because water can expose the eye and lenses to organisms capable of causing severe infection.

When Should Ortho-K Lenses Be Removed?

Remove the lenses and seek prompt advice if there is:

• Eye redness
• Eye pain
• Unusual light sensitivity
• Discharge
• Sudden or persistent blurred vision
• Excessive watering
• A significant foreign-body sensation
• A white spot visible on the cornea

A painful or significantly red eye in a contact-lens wearer should not be treated as routine irritation without professional assessment.

Do the Benefits of Myopia Control Outweigh the Risks?

Increasing levels of myopia are associated with a greater lifetime risk of conditions including myopic macular degeneration, retinal detachment, glaucoma and cataract.

A 2021 risk-benefit analysis considered the potential adverse effects of myopia-control treatments alongside the future risks associated with increasing myopia. The researchers concluded that the potential benefits of reducing myopia progression generally outweigh the treatment risks when myopia management is appropriately prescribed and monitored.

This does not mean that every child requires Ortho-K. Treatment needs to be selected according to the child’s prescription, eye health, maturity, progression risk, lifestyle and ability to safely handle contact lenses.

Is Ortho-K the Best Treatment for Every Child?

Ortho-K is one of several evidence-based options for managing childhood myopia.

Other options may include:

• Myopia-control spectacle lenses
• Daily disposable myopia-control contact lenses
• Atropine eye drops
• Combination treatment in selected cases
• Lifestyle recommendations, including appropriate outdoor time

The best treatment is not necessarily the same for every child. We consider the child’s age, prescription, eye shape, progression history, lifestyle, treatment preferences and capacity to comply with lens care.

Key Recent Research

Select a study below to read a patient-friendly summary of its findings.