Paul Gifford is a part-time senior lecturer at the University of New South Wales and part-time associate professor at the University of Waterloo in Canada. He is the co-founder of Myopia Profile and MyKidsVision.org, which provides education for optometrists and companies on vision research, and MyKidsVision.org provides parent-focused research support information on managing myopia in children.
The University of New South Wales provides funding as a member of The Conversation AU.
If you or your child is nearsighted (difficult to see things far away), you may have heard of orthokeratology.
Orthokeratology, also known as OK or ortho-k, has been around since the 1960s. However, it has recently attracted interest due to its ability to slow the progression of myopia (myopia).
Orthokeratology involves wearing specially designed rigid contact lenses overnight. Like a mold, the lens temporarily reshapes the eye by gently changing the contour of the cornea (the transparent protective outer layer of the eye, like a powerful lens) while you sleep.
This will make a temporary change; when you wake up, you take off the lens and voila! you can see.
It takes about a week to achieve full results, but after that—assuming you wear them every night and remove them every morning—you should be able to spend your days without glasses or contact lenses.
Most importantly, there is sufficient evidence that it can help slow the progression of myopia.
However, like all treatments, orthokeratology has its advantages and disadvantages-the risks need to be fully understood before use.
Read more: Hidden in the obvious: How the COVID-19 pandemic damages children’s vision
Orthokeratology may be an attractive option:
For people who want to replace glasses but find that contact lenses are uncomfortable or inappropriate (for example, they suffer from dry eye, work in a dusty environment or enjoy water sports)
As an alternative to refractive surgery, it is also called laser eye surgery or LASIK. Refractive surgery is permanent, but orthokeratology is temporary; if you stop using lenses, everything will return to normal within a week
For parents of children who may wear contact lenses at school; ortho-k allows children to go to school without glasses or contact lenses, which may be lost or loose during the day.
The upfront cost is higher than the daily wear of contact lenses, and the overall cost of the latter is amortized over time
If you don’t use them every night, the effect will disappear
Compared with not wearing contact lenses at all, the use of all contact lenses brings a higher risk of eye infections.
Some people may think that orthokeratology has a higher risk of infection than standard soft contact lenses. However, this is not supported by research evidence.
A Japanese study compared the results of children with orthokeratology or soft contact lenses for 10 years. It was found that there were no serious adverse events between the two groups, and the frequency of mild and adverse events was roughly equal.
If you get an infection from wearing standard contact lenses or orthokeratology, you will usually be treated with antibiotics. However, it is possible to contract a rare infection called microbial keratitis, which can damage vision.
This is not common. According to a study, if you wear an orthokeratology every night for 1,000 years, you may only have one serious infection.
If you use sterile contact lens solutions and avoid tap water, orthokeratology lens wearers will greatly reduce the risk of eye infections. Tap water contact lenses or lens accessories will greatly increase the risk of infection.
It is now estimated that half of the world's population will be nearsighted by 2050. The World Health Organization has sounded the alarm, saying in a statement:
High myopia greatly increases the risk of severe vision loss such as macular atrophy and glaucoma. Wearing standard glasses cannot reduce its incidence.
Slowing the progression of myopia can reduce the risk of vision-threatening eye diseases. This also means reducing the frequency of vision changes, which can save less glasses replacement costs in the long run.
Myopia progresses faster when young, so myopia control and prevention should be carried out as soon as possible. We don’t know exactly how orthokeratology slows the progression of myopia, but convincing research shows that it is.
If you are considering an orthokeratology for your child, you and your ophthalmologist need to strike a balance. The child must be old enough to deal with it-but if you wait too long, the myopia control benefits it provides will diminish.
Every child is different. Some people are more capable than others to contend with orthokeratology, or are willing to wear it all night. It may feel uncomfortable at first, and some people may find the idea of contact lenses too difficult. It cannot be forced.
Orthokeratology is not the only solution. You can also get special lenses for glasses and soft daily wear contact lenses that help slow the progression of myopia. Seek advice from an ophthalmologist to see all options.
I also suggest that children do no more than two hours of leisure "close work" (ie non-school work: watching screen time or reading a book) in their spare time every day. Parents can also teach children the "20-20 rule" (every 20 minutes of close work, take a break of 20 seconds to see the distance). Outdoor time (two or more hours a day) is also essential for the healthy development of children’s eyes.
However, it is obvious that all myopic children should take measures to control their myopia. It is not enough to give children standard single vision glasses to help them see things, and nothing more is done to help slow the development of myopia.
If suitable for your child, Orthokeratology has one of the strongest research pedigrees to slow the progression of myopia.
Read more: How to keep your contact lenses clean (what will happen if you don’t)
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