Table of contents:
- What is the function orthokeratology (ortho-k)?
- Who needs that
- Preparations that need to be made before ortho-k therapy
- How ortho-k works in correcting minus eye
- Results after ortho-k therapy
- How long do you have to use the lens?
- Are there any side effects or complications orthokeratology?
Contact lenses are commonly used to treat nearsightedness. However, nowadays there are special lenses made by ophthalmologists to correct refractive errors due to nearsightedness. This lens is known as a lens orthokeratology or ortho-k. Ortho-k lenses are used differently from regular contact lenses. Its function is not only to improve temporary vision such as contact lenses, but aims to reduce minus in the eye.
What is the function orthokeratology (ortho-k)?
Lens orthokeratology (ortho-k) functions to correct refractive errors (refraction), especially nearsightedness, by correcting the shape of the cornea of the eye.
Regular use of ortho-k lenses can temporarily change the curvature of the cornea. Ortho-k lenses need to be worn every night while sleeping. That way, without the use of visual aids, eyes who are nearsighted can see better.
Unlike contact lenses that can be purchased without a prescription, ortho-k lenses must be designed by an eye specialist. This therapy is similar in concept to orthodontist braces.
As described, the repair effect of orthokeratology temporary. Vision improvement in nearsighted eyes can return to normal. However, you can maintain the ortho-k repair results if you continue to follow the doctor's instructions for use.
Who needs that
Ortho-k is generally used in the treatment of nearsightedness (myopia) or eye minus.
Mostly, ortho-k therapy is performed to reduce eye minus in children aged 8-12 years. Especially children who experience progressive minus eyes. This means that nearsightedness of the eye gets worse over time.
Children are not recommended to undergo eye refractive surgery, such as LASIK. The reason is, children's vision systems are still developing until they are adults. Meanwhile, LASIK can only be done when the visual system is stable or does not experience tissue development or function.
Ortho-k is a non-surgical treatment option that aims to slow the progression of minus in children. According to the American Academy of Ophthalmology, there is no definite evidence that routine use of ortho-k lenses can inhibit myopic disorders in children. However, everyone with minus eyes is basically still allowed to undergo ortho-k therapy.
Preparations that need to be made before ortho-k therapy
To make ortho-k lenses, the doctor must first perform several eye examinations. The examination that is carried out is a mapping of the cornea of the eye using a tool called a topographer.
Corneal mapping is done by reflecting light from a topographer on the front surface of the eye. From the mapping results, the size and shape of the eye cornea will be known. This examination aims to make the lens adjusted to the condition of your cornea.
How ortho-k works in correcting minus eye
The principles of how the ortho-k and LASIK work in the eye are actually almost similar. Both of them modify the shape of the cornea. The difference is, the results of LASIK treatment can be permanent, meanwhile orthokeratology only lasted temporarily.
The working principle of the ortho-k lens is to apply external pressure to the cornea so that it flattens the front surface of the eye. In minus eyes, the curvature of the cornea is too elongated so that the surface needs to be flattened so that light can focus on the retina.
Lens orthokeratology made of a material that is hard enough to provide enough strength to change the shape of the cornea. Even though they are hard, these lenses are made of a material that is able to absorb air so that the eyes still get an adequate supply of oxygen.
A more even change in the shape of the cornea can only be seen after wearing this lens for a certain period of time.
That's why, you have to wear it every night when you sleep. At first, doctors will recommend intensive use for 1-2 weeks. During your sleep, the lens will correct the shape of the cornea so that in the morning, after removing it, you can see clearly.
From this method of use, nearsightedness can gradually decrease. If the results are optimal, the patient can even see clearly without the aid of glasses.
When wearing ortho-k lenses is stopped, the cornea will return to normal shape. For this reason, in order to keep the curvature of the eye normal so that vision is always well corrected, you need to use this lens regularly.
Results after ortho-k therapy
To get the maximum effect from wearing ortho-k lenses, you need at least regular wear for 1-2 weeks every night. However, minus eye symptoms can begin to improve within a few days of use.
Besides, the results are effective orthokeratology in reducing eye minus also depends on the condition of nearsightedness of each patient. Eyes with a greater degree of minus take longer to correct the refractive error.
During the therapy period, more than one pair of lenses can be used. Usually, there are 3 pairs of ortho-k lenses that are used alternately. This method aims to make the vision correction more optimal. The doctor will explain when you need to change the lens.
How long do you have to use the lens?
After the visual disturbance is corrected according to the desired target, you will use a lens mount (lens retainer). This lens functions to maintain the corrected structure of the cornea of the eye.
That way, the ability to successfully improve vision can last as long as you undergo ortho-k therapy.
How long you have to use the retaining lens depends on the condition of your eye. Your doctor will usually recommend that you wear a retaining lens as often as possible to keep the results of the eye corrections done.
There is really no limit to how long a person should wear ortho-k lenses. As long as your eyes are healthy, you can still undergo therapy orthokeratology as long as it remains under the supervision of a doctor.
According to a study entitled Factors Determining Effective Orthokeratology, a series of ortho-k therapy performed for 6-12 months has been shown to provide the right correction results.
However, it is not certain whether the results of the correction will last long if the patient finally stops therapy. There is still a chance that you may experience deterioration in distance vision again after stopping using lenses.
Study results in journals Overnight Orthokeratology demonstrated long-term ortho-k treatment was indeed effective, but not all parts of the cornea in nearsighted eyes were completely repaired.
Are there any side effects or complications orthokeratology ?
Every medical procedure has side effects, as well as ortho-k.
During the initial therapy period, patients may experience minor side effects such as easy glare due to sensitivity to light and blurry vision. However, this disorder will disappear as the ability to vision increases.
It is also important to know that this therapy is inseparable from the risk of dangerous complications. Several complications orthokeratology to watch out for, namely:
- Bacterial eye infection
- Permanent decrease in vision due to infection
- Corneal clouding which can lead to cataracts
- Change in the original shape of the cornea
- Change in eye pressure
To avoid complications, patients are required to routinely go to an ophthalmologist and follow the doctor's advice. Finally, during therapy you need to keep your hands, eyes and ortho-k contact lenses clean.
