Current Orthokeratology Studies

Below are some of the important studies looking at Orthokeratology. This is current data and will continue to be updated as this wonderful procedure continues to have more studies examine it more closely.
The Study Data Summarized
COOKI (Children’s Overnight Orthokeratology Investigation)

The purpose of this study was to determine the safety and efficacy of overnight Orthokeratology in eight to eleven year old children. The conclusion of this study showed that Ortho K LK contact lenses worn during sleep provide adequate vision for myopic children to be able to function throughout the day without wearing glasses or contact lenses. 78.4% of children age eight to eleven years are able to successfully adapt to rigid gas permeable contact lens wear. There were no adverse ocular effects.

COMET (The Correction of Myopia Evaluation Trial)
This study evaluated whether Varilux progressive addition lenses slows down the rate of juvenile onset myopia versus single vision lenses. This was a five year study, six to eleven year olds, 48% male/52% female, ranging 1.25 diopters to 4.50 diopters of myopia. The use of the progressive addition lenses compared with the single vision lenses slowed down the progression of myopia by a small amount during the first year and the difference was maintained over the next two years. It was concluded however that this small decrease in the rate of progression of myopia does not warrant a change in the clinical management of myopia.

CLAMP (Contact Lens And Myopia Progression)
This study had several goals. To evaluate the effect of rigid lenses on myopia progression iun children. To determine the mechanism of effect if one exists. To examine the efficacy of rigid contact lenses for the treatment of myopia in young children. To compare vision and comfort issues between rigid and soft contact lens wearers. The conclusions of this study are as follows: Rigid gas permeable lenses produce a slower rate of progression of myopia in children than soft contact lenses. Although corneal curvature changed, the axial growth was not significantly different between the groups. The decreased refractive error progression is not accompanied by slowed axial growth. The corneal curvature changes during corneal reshaping contact lens wear are reversible. The treatment effect experienced in the CLAMP study may not be permanent. Most of the effect on refractive error was limited to the first year of the trial. The study did not indicate that rigid gas permeable lenses should be prescribed primarily for the intent of myopia control.

MYOPIA CONTROL (Houston Study)
This study examined the control of myopia progression comparing rigid gas permeable contact lenses versus spectacles. The results showed that the mean increase in myopia for the gas permeable lens was 0.42 diopters per year versus a mean increase in myopia for the spectacle wearers of 0.78 diopters per year. The mean increase in axial length for the gas permeable lens was 0.22 mm per year versus a mean increase in axial length for the spectacle wearers of 0.31 mm per year. The study showed that the decrease in progression of myopia using gas permeable lenses is attributable to mix of axial length growth reduction and corneal flattening.

LORIC (The Longitudinal Ortho-k Research In Children)
This study looked at several factors. It was to determine whether Orthokeratology can effectively reduce and control myopia in children. It also compared Orthokeratology treatment with single vision spectacles. It monitored the growth of axial length and the vitreous chamber depth. It also monitored corneal curvature and the relationships with changes of refractive errors. The conclusions of the study found that the subjects found post Orthokeratology unaided vision acceptable in the daytime. The mean increase in axial length for the Orthokeratology group was 0.14 mm per year compared with the mean increase in axial length for the spectacle lens wearers of 0.27 mm per year. In the spectacle wearing group, the eye elongation is faster in those with higher baseline prescriptions. Orthokeratology would benefit higher baseline prescriptions as eye elongation is slower in these subjects. Higher myopia showed greater slowing of progression in the Orthokeratology group. This study is to determine if wearing Orthokeratology lenses on an overnight basis stops or slows the progression of myopia in children. The group being studied is eight to eleven years old. This group will be compared to spherical soft lens wearers. This study is currently underway so no data is yet available.

A STUDY FROM HONGKONG UNIVERSITY

What is ortho-k:
1.Is a form of vision correction.
2.It involves the modification of the corneal shape through the application of specially designed, high oxygen permeability rigid gas permeable (RGP) contact lens in order to temporarily reduce the amount of myopia and astigmatism.

Who are suitable for this therapy?

1.Individuals who can normally wear RGP lenses and
2.Who do not have more than 5 D of myopia and with less than 1.50D of astigmatism**.
3.Whose myopia are progressing rapidly.
4.Higher myopia (e.g. 6.00D) reduction may be possible for some patients. However, the success rate has not been published.
Pros:

1.In successful overnight wear, good vision can usually be maintained throughout the day after lens removal.
2.Night therapy brings convenience to those who do sports or who do not like to wear conventional contact lenses or spectacles during the day.
3.Our recent research has shown the treatment to be effective in slowing myopic progression in children.
4.On average, ortho-k can usually reduce myopia of 4.00D within two weeks. However, individual variation does exist.
5.Complications associated with conventional contact lens wear, such as dryness and irritation from dust can be avoided.
6.The treatment is reversible and can be stopped anytime. The eyes will soon resume their normal condition thereafter.
Cons:

1.Ortho-k is NOT a CURE for myopia. The treatment effect will wear off gradually after stopping lens wear.
2.Ortho-k lenses require more time to fit compared to conventional contact lenses. Aftercare consultations are more frequent to ensure effective and safe treatment.
3.Some contact lens-related problems, such as solution sensitivity, infection or corneal epithelial trauma may occur, though the risk of complication is very dependent on compliance. Improper use of these lenses can lead to corneal ulceration.
4.Treatment effect may vary and is patient dependent. Some patients may not be able to achieve the desired effect.
5.During the course of treatment, temporary spectacles may be needed.

What should I do if I am interested in the treatment?
Make an appointment with a registered optometrist who provides ortho-k services Learn more about ortho-k

what would be involved, and your responsibilities if you decide to undergo this treatment.
Have a thorough eye examination to evaluate whether you are suitable for the treatment or not.
A treatment plan should be designed for you if you are suitable.
What are the comlications involved

All myopia reduction methods have their advantages and disadvantages, and there is a risk of complication with any treatment.
Remember complications can happen anytime! Minimise the chance of these complications through good communication with your optometrist, strict compliance and regular aftercare consultations.

Final advice
For a patient who wishes to have temporary myopia reduction of myopia, ortho-k is one (but not the only) alternative. The patient is strongly advised to seek professional advice from her/his optometrist, to find out clearly what ortho-k involves for her/him, to avoid using the treatment cost to determine where s/he should have the treatment, and after commencing the treatment, to be strictly compliant. Rapport and communication between the patient and her/his optometrist is very important to
avoid unrealistic expectations
maximise safety
allow the patient to enjoy healthy lens wear
No treatment is without risk, but careful compliance by the users will reduce the chance of serious complications to a minimum.

SAFETY AND PRECAUTIONS FOR ORTHO- K LK LENS USERS

Ocular Changes During Sleep
Five major 'environment' changes when the eyes are closed.
There is no lid actions (blinking) to aid tear exchange and to eliminate debris.
There is a reduction in the oxygen supply to the cornea.
The tears become more acidic.
There is an increase in corneal temperature which can lead to increased corneal metabolic activity.
There is change in tear osmolarity due to no tear evaporation.
All these changes can affect contact lens wear.

Compliance

1.To enjoy symptom-free contact lenses, compliance is very important. Proper usage of the lens and lens care is of utmost importance. If significant bacterial contamination is introduced into the eye, an eye infection may result, therefore, strict hygiene in handling contact lenses is absolutely essential. Reports of any serious complications associated with contact lenses are rare, but usually the cause of these rare cases has been traced to some serious neglect by the patient of the instructions on hygiene, wearing schedule or maintenance procedures.
2.Optometrists/contact lens practitioners who practice Ortho-k should also ensure that they provide professional and ethical services to their patients, are properly equipped to provide Ortho-k service, and are kept up to date with their skills. It is important to communicate effectively with the patient, gain the patient's confidence, establish good rapport, and to avoid overstating the advantages and disadvantages of Ortho-k. Careful assessment and monitoring of the patient's ocular integrity is also essential to minimise complications.
Important points for patients to note

1.EACH TIME, before handling the contact lenses, wash your hands thoroughly ensuring that the sides of the fingers and the palms are cleaned. Ensure that your fingers are free of lint, cosmetics, hand lotions, hair oils, nicotine etc.

2.Contact lenses are made of plastic materials and if handled carelessly they may be scratched, distorted, chipped or split. These imperfections may be too small for naked eye observations. They can be located by your optometrist/contact lens practitioner with proper equipment during follow-up consultations. Small defects on the lens may not cause any symptoms but may allow accumulation of debris that can harbour microorganisms.

3.Do not slide or scrape a lens across a tabletop and be sure that your fingernails do not scratch the surface or dent the edge of the lens.

4.If you suspect that your lens might be damaged, have it checked by your optometrist/contact lens practitioner.
Use of contact lens solutions:

1.The tip of bottles should not come into contact with the lens, fingers or any other surface to minimise the risk of contamination.
2.The soaking solution should be changed every day, the lens container should be cleaned before use.
3.Do not change your solutions without consulting your optometrist/contact lens practitioner first, some solutions may not be compatible with the type of lenses you are using or may contain different preservatives which may cause allergy response
4.The time required for adaptation and the reactions to Ortho-k lens wear vary between individuals. It is important to be able to distinguish between "normal" adaptation problems and signs or symptoms that require advice from your optometrist/contact lens practitioner. 5.All contact lens accessories (including suckers and lens case) should be cleaned properly before use, disinfected appropriately and replaced regularly.
**Parents of children who are unable to handle their contact lenses hygienically should be prepared to do these for their children, or if not, SHOULD NOT allow their children to undergo Ortho-k treatment.

A study on Orthokeratology :Hongkong University Project

How It Controls Myopia Progression
Ortho-k can be defined as a technique where the cornea is progressively reshaped using specially made contact lenses, thereby reducing myopia. New technology has significantly accelerated the reshaping of the cornea. However, unlike LASIK, ortho-k does not lead to permanent change. Ortho-k is a treatment for reducing myopia, and it is NOT a cure. The myopia reduction effect is only temporary and the patient needs to continue to wear the lenses to maintain the effect. Our research study on myopia control with ortho-k lenses has shown that eyeball elongation in myopic children was about half the elongation observed in myopic children wearing spectacles. Effectively, this means that the progression in myopia in children undergoing ortho-k was slower by about 50% when compared to children wearing spectacles.

Some Frequently Asked Questions

Can ortho-k reduce myopia?
A1: In general, ortho-k can reduce myopia of up to about 4.50D. In some cases, reduction of up to 6.00D myopia has been known to be possible. However, it is very patient-dependent.

Can it reduce astigmatism?
A2: With most of the current lens designs, the treatment can only reduce myopia. However, new lens designs like 5 curve lenses are currently being developed for correcting astigmatism.

Can ortho-k control myopia progression?
A3: The results of recent research show that myopic progression is slower by about 50% in the children wearing overnight ortho-k lenses compared to children wearing spectacles.

How do I know if I am suitable for this treatment?
A4: You will need to consult an optometrist who will carry out a thorough eye examination to determine if you are suitable to attempt this treatment. Rapport between you and your optometrist is very important.

Physicians have said that ortho-k will hurt the eyes. Is this true?
A5: If not used properly, yes. Some discomfort (due to lens sensation) may be experienced during the adaptation period but the treatment should not hurt the eyes if properly fitted, used and managed.

My friend and I both have ortho-k treatment. Why is it that my friend can have clear vision after removing the lenses but I cannot?
A6: It depends on the amount of myopia you both have and the success of the treatment. Ortho-k is dependent on the individual. For some patients, myopia can be reduced very quickly while for others, reduction may be very slow. For example, patients with significant pre-ortho-k astigmatism, post-ortho-k vision will be poorer compared to another individual with no significant astigmatism

Why do I have ghosting/blurring of vision during the daytime?
A7: This may be due to different reasons:
the lens/lenses was/were not centering well
the retention time was not long enough
myopia was not completely reduced
presence of significant residual astigmatism
Since this problem is likely to be related to lens fitting, you need to consult your practitioner as soon as possible. Problems related to poor lens fitting may result in other ortho-k complications such as corneal staining.
Will the results of the treatment or the eye be affected if my child rubs his/her eyes during sleep?
A8: Possibly. If the rubbing dislocates or decentres the lens, vision may not be as good the next morning after lens removal .Mild rubbing may lead to superficial corneal abrasion which usually heals within a few hours after lens removal. The severity of injuries inflicted in such cases will depend on how hard your child rubs his/her eyes.

Will the results be affected if I sleep less than 6 hours a day?
A9: Inadequate sleep is not healthy for your eyes, whether you wear ortho-k lenses or not. Inadequate sleep would also cause discomfort, e.g. dry or sore eyes which may affect lens wear. Also, if you sleep less than 6 hours with your ortho-k lenses, optimal myopia reduction and retention effect may not be achieved .

Do I need to wear spectacles before achieving the reduction target?
A10: You may need to wear temporary glasses during the treatment procedures as reduction is not instantaneous but progressive. Your optometrist will be able to advise you on this.

Can I throw away all my glasses after achieving the reduction target?
A11: It is advisable to keep your glasses as there may be occasions when you may need to stop lens wear for a few days and you will then need to wear glasses. Example, if you lost a lens, you will need to stop lens wear for a few days to wait for the new lens to be delivered

CORNEA

CORNEA

The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid . Because transparency is of prime importance ,the cornea does not have blood vessels and it receives nutrients via diffusion from the tear fluid at the outside and the aqueous humour at the inside and also from neurotrophins supplied by nerve fibres that innervate it. It borders with the sclera by the corneal limbus.

Size:

In humans, the cornea has a diameter of about 11.5 mm and a thickness of 0.5–0.6 mm in the center and 0.6–0.8 mm at the periphery. Transparency, avascularity, and immunologic privilege makes the cornea a very special tissue. The cornea is the only part of a human body that has no blood supply; it gets oxygen directly through the air.In humans, the refractive power of the cornea is approximately 43 Diopters.

Treatment and management

Surgical procedures
Various Refracive Eye Surgery techniques change the shape of the cornea in order to reduce the need for corrective lenses or otherwise improve the refractive state of the eye. In many of the techniques used today, reshaping of the cornea is performed by photoablation using the excimer laser.

If the corneal stroma develops visually significant opacity, irregularity, or edema, a cornea of a deceased donor can be Transpalanted. Because there are no blood vessels in the cornea, there are also few problems with rejection of the new cornea.
There are also synthetic corneas (keratoprostheses) in development. Most are merely plastic inserts, but there are also composed of biocompatible synthetic materials that encourage tissue ingrowth into the synthetic cornea, thereby promoting biointegration.

Non-surgical procedures

ORTHOKERATOLOGY is a method using specialized hard or rigid gas-permeable contct Lenses to transiently reshape the cornea in order to improve the refractive state of the eye or reduce the need for eyeglasses and contact lenses.

ALTERNATIVE TO LASIK SURGERY

IDEAL FITTING GUIDE:

1.First an initial assessment appointment to include a full Sight Test and Computerised Corneal Topographical Scan for assessment of the general condition and health of your eyes and also to discuss the likely effectivity of the procedure in your own case.
2.A pair of trial lenses are then issued for an overnight trial and your optometrist will see you the next morning. After another Sight test and scan, the change in your corneal shape and reduction in prescription is assessed. If the fit is not correct then another overnight trial may be needed.
3.Once your optometrist has established the correct fit and that he can reduce your myopia so that you will be able to achieve normal vision, a pair of OrthoK lenses will be ordered.

4. When these arrive, the fit is assessed and you will be given them to wear every night for a week. Excellent vision and comfort are normally maintained whilst wearing OrthoK Lenses.

5.You will be assessed after a week and if any modifications are needed a new pair of lenses will be ordered.
This series of OrthoK Contact Lenses, made from High Oxygen Permeable Rigid Material, gently reshape the Cornea towards less curvature and a more spherical shape. This reduces Myopia and Astigmatism whilst dramatically improving unaided eyesight.
Most of the visual changes occur rapidly in the first few days and stabilisation procedures then follow at a slower pace over the next few months. The program length varies between 3 and 6 months depending upon the degree of visual error.
6.When the maximum results are achieved, the final pair of lenses are worn to stabilise the new Corneal shape.
The final wearing time depends on many variables, but the treatment aim is to have good unaided vision all or most waking hours, with Lenses being worn overnight . Some patients will be able to wear their Lenses every other night.
WHAT ARE THE ADVANTAGES OF ORTHOK?
-Good Vision without Spectacles or Contact Lenses for Most of the day.
-It is Not a Surgical Procedure
-It is Reversible.
-It is Non-Invasive.
-It is Modifiable.
-It Does Not Hurt.
-Using well established Contact Lens Fitting Techniques mean that there are very few risks.

ALTERNATIVE TO LASIK SURGERY

Wouldn't it be great if your nearsightedness could be corrected while you sleep? It might sound far-fetched, but it's a reality for some people. It's called orthokeratology, or ortho-k, and it is available throughout the country.

Here's how it works: When you sleep, you wear special contact lenses that gently reshape the surface of your eye, so you can see clearly even after you remove the lenses. The effect is temporary — generally enough to get you through a day or so, but you must wear the special lenses each night.

HOW DOES IT WORKS

Myopia is caused by light coming into the eye in such a way that it doesn't focus properly on the retina.This problem is corrected by using eyeglasses or regular contact lenses to re-focus the light rays.
A similar result can be achieved by reshaping your cornea. LASIK is a surgical way to do this. Ortho-k contact lenses flatten your cornea without surgery, enabling light to focus properly on your retina, resulting in better vision

Is Ortho-k Comfortable?

Some people have comfort issues with daytime wear of GP contact lenses (also known as RGP or "oxygen permeable" lenses), which are used for ortho-k. With GPs, a sensation of lens awareness can result from interaction of the eyelid with the edge of the lens during blinking. (This doesn't happen with soft lenses because they are larger and remain tucked under the eyelids.) But since ortho-k lenses are worn during sleep, blinking and lens awareness are generally not a problem.

WHY YOU SHOULD HAVE ORTHO K LENSE INSTEAD OF LASIK

Ortho-k works best for people who don't want to wear glasses or contact lenses all day, every day — but don't mind wearing contact lenses at night, or occasionally during the day.
If your primary goal is to be glasses- and contacts-free during the day, then ortho-k might be a good alternative for you. However, if you want to eliminate the bother of contacts altogether, then ortho-k is not likely to satisfy you.
Ortho-k may be a good option if you suffer from dry eyes. It's been found that this condition is sometimes worsened by LASIK.
-The procedure is REVERSIBLE (Excimer is not!).
-It does not involve post-operative pain.
-It does not leave the hazy vision often experienced by patients following laser surgery.
-There is no loss of Bowman's membrane (the tough protective layer just under the Corneal surface).
-Both eyes are done together (rather than several weeks or months apart).
-Changes in prescription over time can be dealt with (unlike Excimer).
-OrthoK is significantly cheaper.

Can it also controls Myopic Progression?

In 2006 and 2007 papers presented at the British Contact Lens Association and the Global Ortho Keratology Symposium indicated the possiblility of orthokeratology slowing or stopping myopic progression. This was found to be effective in children in Hong Kong and is the subject of wider study to verify this data
Unlike LASIK, ortho-k is reversible. If you try reshaping lenses and later decide you want laser eye surgery instead, you can do that. But for a period of time before surgery (possibly several months), your surgeon would have you stop wearing your lenses so your corneas can revert to their natural shape.