What is Ortho-K

Key Points

Ortho-k is short for orthokeratology. During sleep, Ortho-k lenses gently reshape the cornea, enabling clear daytime vision without the necessity of eyeglasses or conventional contact lenses

Correction from ortho-k is temporary and requires continuous overnight wear. 

To achieve a great lens fit at all times, ortho-k typically require more appointments than soft contact lenses.

People new to ortho-k may initially find Ortho-K lenses less comfortable than soft contact lenses, yet comfort typically improves significantly within the initial week.
Ortho-k is safe to wear as long as follow-up care visits are attended and lens wear and care guidelines are followed.

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In this article

Orthokeratology (ortho-k) refers to specialized rigid contact lenses designed to be worn overnight. They reshape the cornea, eliminating the need for daytime glasses or contacts. Aside from vision correction and myopia control, ortho-k offers lifestyle advantages, especially for active youngsters engaged in sports and recreation.

This article will give you a broad understanding of ortho-k lenses.

• How do ortho-k lenses work?
• Is ortho-k permanent?
• Can ortho-k lenses slow or reverse myopia?
• How are ortho-k lenses fitted?
• Do ortho-k lenses hurt?
• Is ortho-k safe?
• Are ortho-k lenses difficult to wear?
• Is my prescription suitable for ortho-k?
• Is ortho-k worth it?
• Where to buy ortho-k lenses?

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How do ortho-k lenses work?

The eye works almost like a camera. It has two lenses that focus light. A camera uses those lenses to focus the light onto a chip or film, while the eye focuses that light onto your retina.

The main focusing lens is the cornea. The cornea sits at the front of the eye and has a fixed focus strength, providing around 75% of the eye's focus power.
The interior lens is also flexible and allows focus change at different distances. This lens is responsible for keeping objects in focus as they move closer to you.

Orthokeratology (ortho-k) lenses work to correct myopia by temporarily flattening the cornea in a carefully controlled manner. This flattening is customized to match the level of myopia, with adjustments for more severe cases. The resulting corneal flattening reduces its focusing power, which helps counteract myopia caused by excessive focusing ability. This process restores clear focus on the retina and improves vision.

Ortho-k lenses are worn overnight, taking advantage of the flattening process that occurs during sleep. When removed during the day, the changed corneal shape temporarily reduces myopia, leading to better and clearer vision.

Is ortho-k permanent

Ortho-k flattens the cornea temporarily, but this effect fades within a few days after stopping lens use. This happens because ortho-k mainly affects the front surface of the cornea, which is gently compressed and expanded to match the lens shape. Once you stop wearing the lenses, the cornea gradually returns to its original state.

Think of it like sitting in the same spot on a couch all night – you leave an impression on the cushion that gradually goes away during the day. Similarly, with repeated overnight ortho-k, the corneal change becomes stronger over time. It usually takes about a week of wearing the lenses at night to see the full effect.

Compared to permanent solutions like laser surgery that involve removing corneal tissue, orthok's temporary effect has advantages. You can stop using ortho-k at any time and your eye will go back to its natural shape. Research shows that most of the ortho-k effect reverses within the first week after you stop wearing the lenses. This temporary effect is especially helpful for children, as it allows adjustments to the ortho-k lens design as their eyes continue to grow and change.

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Can ortho-k lenses slow or reverse myopia?

Myopia, or nearsightedness, is becoming more common in children and can have lasting negative effects on vision and eye health as they grow up.

The good news is that there are effective ways to slow down myopia progression in children. These include using special glasses or contact lenses and encouraging habits like spending less time on close-up activities and more time outdoors.

Among the methods to control myopia, orthokeratology (ortho-k) has shown to be particularly effective in slowing down myopia progression in children by about half. It has more research supporting its effectiveness compared to other methods.

How are ortho-k lenses fitted?

Specialized equipment and expertise are needed for a successful fit of ortho-k lenses. Typically, optometrists or eye doctors handle this process.

To determine if someone is a good candidate for ortho-k, their eye prescription and the shape of their cornea (the front part of the eye) are assessed. A corneal topographer, a device that takes pictures of light patterns on the eye, is used for measuring corneal shape. Computer software then creates a 3D model of the cornea from these pictures, helping design a customized ortho-k lens.

A computer model of the cornea is used to find the best ortho-k lens fit. The doctor may pick a ready-made lens or use software to design a custom lens based on the model.

No matter the approach, the tried-and-true process usually results in a well-fitting ortho-k lens, like a tailor-made suit. This step is often where the doctor determines if ortho-k will likely work for you.

If you're a good candidate, you'll learn the steps for the lens fitting process. Ortho-k fitting takes more visits than regular daily contact lenses because each ortho-k lens is personalized for your eye.

The number of visits needed for a successful ortho-k lens fit can vary. Typically, you'll have these appointments:

1. Initial refraction and eye measurements: These data will guide the lens ordering process.
2. Lens collection appointment: Here, you'll learn how to correctly apply, remove, and care for your ortho-k lenses.
3. Morning follow-up after the first night of lens wear: This visit confirms the success of overnight lens wear and provides additional guidance on lens handling. While an early assessment of lens fit may be possible, the full effect is usually realized after a week of overnight use.
4. Morning follow-up after approximately 1 week of overnight lens wear: At this point, the complete effect is expected, and your optometrist or eye doctor can determine if any adjustments to the lens fit are needed. Note that achieving the full effect might take longer in some cases, so it's normal if the desired outcome isn't fully realized during this visit.

Follow-up appointments will vary based on potential adjustments required for optimal lens fit. Understanding that ortho-k lenses are custom-designed and necessitate wearing for a full assessment of the eye's response is important.

In some cases, practitioners may extend the wearing period a few nights to assess fit, while in others, slight design modifications could be considered. Ultimately, once the best fit is achieved, the frequency of appointments will reduce.

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Do ortho-k lenses hurt?

It might seem like changing the shape of the eye would be painful, but it's generally not the case. Ortho-k lenses are carefully designed to fit well and minimize discomfort. When you start wearing them, you might feel a bit like there's something in your eye, similar to having a tiny speck of dust. This feeling fades as your eye gets used to the lens.

Your eye might produce extra tears at first, thinking the lens is foreign. But this usually gets better quickly, and you'll likely forget the lens is even there. Think of it like breaking in a new pair of shoes – they might be a bit uncomfortable at first, but soon you won't even notice them.

Is ortho-k safe?

Wearing any type of contact lens, including ortho-k lenses, increases the risk of eye infection because the lens is touching your eye directly. Ortho-k lenses add a bit more risk when worn during sleep with closed eyes, though they are safer overnight than soft contact lenses. During sleep, blinking that naturally cleans and protects the eyes happens less, making the eyes more vulnerable.

The good news is that following proper cleaning and avoiding tap water contact with lenses and their accessories can greatly lower the infection risk. Remember, it's vital to never let tap water touch contact lenses, including ortho-k lenses, and the tools you use with them, like cases or applicators.

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Are ortho-k lenses difficult to wear?

Ortho-k lenses are user-friendly and convenient. They're made from a rigid material, making them easy to handle, and their smaller size simplifies application. While removing them might require a bit of practice, wearing them overnight eliminates daytime concerns about lens stability.

Is my prescription suitable for ortho-k?

Ortho-k is commonly used to fix myopia, and it can also work for hyperopia, astigmatism, and presbyopia. It's generally effective for up to -4.50D of myopia with up to -1.50D of astigmatism, as approved by the FDA. While it can correct higher levels of myopia, success may vary. Individual factors matter, so use published ranges as a guide and consult an optometrist for advice

Is ortho-k worth it?

The answer depends on your motivation, situation, and cost.

Many people are happy with ortho-k lenses, especially for slowing myopia in children. But, getting used to them takes time, as fitting ortho-k takes longer than soft contact lenses. They might be less comfortable initially.

Over time, though, research suggests that some who had dry eyes with soft lenses find ortho-k more comfortable and even prefer them.

The initial cost of ortho-k lenses is usually higher than daily wear contact lenses due to more consultation time and higher lens expenses. However, ortho-k lenses are more durable, which can balance out the cost over time.

After considering cost, personal preference comes into play. Ortho-k lenses are ideal for active individuals bothered by daytime contact lens wear.
Parents appreciate the control ortho-k provides as lens care is entirely at home.

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Where to buy ortho-k lenses?

To ensure proper fitting and suitability for you or your child, ortho-k lenses should be obtained exclusively from a qualified optometrist or eye doctor. Specialized equipment is necessary for accurate eye measurement and calculating the appropriate lens fit. Additionally, ongoing evaluation of the effects of ortho-k lens wear requires professional expertise. The intricate lens design and the need for continuous assessment make online purchasing of ortho-k lenses unfeasible.

References

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