What is orthokeratology?
Orthokeratology is a therapy in which specially adapted contact lenses are worn at night while sleeping. The lens gradually moulds the cornea so that when the patients takes it out in the morning they can see well for the rest of the day without the need for glasses or normal contact lenses.
How does the lens work during sleep? Is it quick to take effect?
When we sleep with the orthokeratology lenses in, our sight gradually improves and over time we start to notice the effects. In the case of a myopia of 4 dioptres it will take around 2 weeks before we can see well all day without need for glasses or contact lenses. The exact time necessary will vary from person to person. Meanwhile patients will be provided with disposable contact lenses to compensate the myopia that has yet to be corrected. Thus patients will always see well right from the time they start to use orthokeratology; first with the aid of the disposable lenses, and then eventually without the near for glasses or normal contact lenses at all.
Who is it aimed at?
Orthokeratology can be used by anyone from children of 5-6 years, to those of 50 or 60. In children, the main objective is to slow down the myopia and prevent it from increasing.
In adults, it is used in those cases in which the patient does not wear contact lenses during the day. This means that there is no minimum or maximum age limit, it is simply necessary to adapt the contact lens.
Is there a limit of dioptres?
In the case of myopia, it can be treated easily for prescriptions of up to 4 or 5 dioptres. Nevertheless, it can also be treated in patients with up to 8 or 9 dioptres.
As for hyperopia, it can be used in cases of up to 3 or 3.5 dioptres and, in cases of astigmatism, between 3.5 and 4.00 dioptres.
In any cases, a pesonalised and detailed study is required that will determine who is a good candidate, given that no two eyes are the same.
|rEFRACTIVE ERROR||dioptrE LIMIT (general aprox. RULE)|
|Hyperopia||Up to 3.5 dioptres|
|Astigmatism||Up to 4 dioptres|
|Myopia||Up to 4 or 5 dioptres (possibly up to 8 or 9)|
Can a prior test be carried out to determine whether orthokeratology is an option for the patient?
Yes. Before starting the adaptation we have to evaluate whether the patient meets the requirements to be a suitable candidate for orthokeratological treatment. To do this we carry out a test called corneal topography that involves a three dimensional map of the cornea in order to determine whether it is possible to mould the patient’s cornea.
We also evaluate the surface of the eye, the integrity and quality of the tear film. All of this, combined with the dioptres to be treated, will enable us to evaluate whether the patient is a suitable candidate for orthokeratology.
How is a lens adapted for a patient?
The adaptation is more specific than that of a conventional contact lens, given that the lens is designed based on the patient’s corneal topography, as if it was a mould. In addition, the corneal topography at each check up visit will enable us to monitor the changes that we undergo. We should keep in mind that it is not a contact lens in its use, but that the objective is to mould the cornea. This means that it is normal that during the first few days or weeks of adaptation frequent visits are required and it may even be necessary to carry out a change of lens to determine which works better.
Is orthokeratology permanent?
No. Orthokeratology causes a temporary moulding effect on the cornea. On removing the ortho-k lenses in the morning after having slept with them in, the patient will see well throughout the day. But if you stop wearing them at night then after 4 or 5 days the eye will completely recover its previous shape and the patient will revert to the dioptres of their previous prescription.
I was always told that you should never sleep with contact lenses in. Are ortho-k lenses safe?
It’s true that contact lens experts always say that you shouldn’t sleep with conventional contact lenses in. Nevertheless, orthokeratology lenses are made with a special ultrapermeable design that allows oxygen to pass and means that we can sleep with them all night, without this causing any added risks for the patient or the health of their cornea.
How often should the lenses be used?
Ortho-k lenses should be worn every night. If they are not worn one night then vision will probably not be so good the following day. Some patient with low myopias can just wear the contact lenses on alternate nights but, beforehand, they will have needed wear them every night in order to enjoy good vision all day.
Can ortho-k lenses reduce myopia?
It is important to keep in mind that orthokeratology neither cures nor eliminates myopia. In the case of adults, it can keep it corrected for the day thanks to night-time use of the lenses, which removes the patient’s prescription/refractive defect for the day.
In the case of children it is slightly different, as we use orthokeratology to try to prevent the myopia from increasing. It has been statistically demonstrated that, by using orthokeratology, the increase in myopia is 47% less than with the use of conventional contact lenses.
Will I see well with my lenses in?
Yes you will. It is a contact lens that is not intended to provide good vision while we are wearing it, but we can see well with the lens in and if we have to get up at night to go to the bathroom, we will be able to see correctly without any problems. It is not, however designed for this aim, but to provide us with perfect vision when we take it out.
How often will I need to change the lenses?
Manufacturers recommend changing contact lenses every year. This is basically to guarantee healthy eyes. Perhaps the contact lenses could last for slightly longer, but it is very important to reduce risks for the eyes, as we are sleeping with the ortho-k lenses in and they need to be in perfect condition. For this reason, a yearly change of lens is recommended.
Do ortho-k lenses require special care?
They require specific care that isn’t so different from conventional lenses. Basically, when we get up, the normal lenses must be removed and left in a special liquid for the whole day and they should then be put in again the following night. It is important to fill the lenses with artificial tears before putting them in, so that throughout the night there is always tear lubrication between the contact lens and the cornea. This will give the lenses extra safety as the cornea is moisturized whilst the lenses are worn.