Ophthalmology 101: Reducing Myopia with Orthokeratology Lenses
Orthokeratology is a field of ophthalmology that has been around since the 1940s. It focuses on using special contact lenses to temporarily reshape the cornea in order to reduce myopia (short-sightedness), mainly in children. Dr. Yunyan Wu, one of the talented ophthalmologists at the Eye Clinic at Beijing United Family Hospital (BJU), explains more.
How established is the field of orthokeratology? Are there any future developments expected?
Orthokeratology is a non-surgical procedure that can temporarily correct refractive errors (mainly for myopia and astigmatism). It also helps to slow down the progression of myopia by utilizing rigid, gas-permeable contact lenses to reshape the cornea so that objects can be focused on in the retina without wearing glasses.
Orthokeratology lenses (OK lenses) can also be used in children to slow down the progression of myopia by 50% when compared to simply giving children spectacles. The technique has been used for more than 10 years and, while it seems to work for many people, it’s not for everyone.
The use of OK lenses has been the subject of much research in recent years. Clinical trials are still being carried out, some of which have successfully lowered the percentage of atropine. They may have some effectiveness, but these have not yet been approved in China.
Are the lenses painful?
At the beginning, patients may feel a slightly uncomfortable foreign body sensation, but, after a few days, they will get used to it.
OK lenses are more uncomfortable than soft contact lenses because they are rigid and gas-permeable. In that sense, they are more like hard contact lenses. But since they are more gas-permeable and have anti-protein properties (unlike traditional soft contact lenses), they are safer to wear.
The material of the OK lens is more like that of hard contacts. One big difference is that OK lenses are specially shaped to lightly press the cornea, causing it gradually to be reshaped to the correct shape for focused vision.
Should the lenses be changed as the cornea changes shape?
Yes. If the cornea shape changes, then the OK lenses should be changed as well. Also, if the progression of the patient’s myopia changes, then the OK lenses should be changed. Your doctor will decide how often to do the refraction.
Are there any potential side effects?
Eye infection. Patients should pay special attention to the proper insertion and removal techniques for their OK lenses and follow appropriate hygiene care procedures to avoid infection.
In addition, corneal epithelium cell defects can happen if the OK lens is not suitable for the patient, so it’s important to see the doctor routinely as directed. If parents find that their child develops redness, tearing, or a sudden aversion to light, then they should bring their child to their eye doctor.
What are the suggested age limits for this process?
Chinese regulations dictate that a child should be over 8 years old in order to do the procedure, as the corneas of younger children are not suitable. Also, if the child is too young, they will struggle with the sensation of wearing the contact lenses.
As for the upper limit, usually there is no explicit provision. After the age of 40, some people start to develop presbyopia and that means that while OK lenses can help correct their vision for long distances, their near-distance vision will be blurry. For this reason, we have to talk with the patient before suggesting OK lenses, and we will only have them use the lenses if they understand the risks and agree to go forward.
Which eye patients would not be recommended for this procedure?
If the degree of myopia is above -5.00DS or the degree of astigmatism is above -1.50DC, then the patient should not get OK lenses. Those with eye diseases, dry eye syndrome, eye allergies, or non-regular sleeping hours should also not get them.
Could a pregnant woman use this to avoid the eye changes that happen during pregnancy?
Usually not. In pregnant woman the eyeball will change a little, but it will change back after pregnancy, so OK lenses aren’t suitable. We also do not suggest that pregnant women wear OK lenses because if they develop an eye infection, they may not be able to use eye drops because the eye drops may hurt the fetus.
Would children still need to participate in eye exercises should they get these contacts?
It is best for children to continue participating in their regular eye exercises when they wear their OK lenses, as the lenses only slow down the progression of myopia, they don’t eliminate it completely.
BJU is offering a 20% discount on OK lenses so that you can improve your vision while you sleep! This offer is valid through September 15, 2017. Terms and conditions apply. For more information or for a consultation, please call our Eye Clinic at 5927-7037 or our 24hr Service Center at 4008-919191.
Dr. Yunyan Wu is a member of the talented ophthalmology team at Beijing United Family Hospital's Eye Clinic. She has been an ophthalmologist for over 20 years.