This study had several goals. To evaluate the effect of rigid lenses on myopia progression in 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.

SMART
(Stabilizing Myopia by Accelerating Reshaping Technique)

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.

Abstract: The use of Orthokeratology for overnight wear raises many questions of safety, efficacy and the effects of myopia stabilization. Orthokeratology or corneal reshaping produces a temporary reduction of myopia by changing the shape (flattening) of the cornea, which is elastic in nature. Flattening the cornea reduces the focusing power of the eye, and if the amount of corneal flattening is properly controlled, it is possible to bring the eye into correct focus and compensate for myopia. Upon removal of the contact lens, the cornea retains its altered shape for a period of time. The global prevalence of myopia is increasing significantly in the school age population. It is estimated that one billion of the six billion people in the world are myopic. (3) Not only is the prevalence increasing but the degree of myopia has also increased. The prevalence of myopia in the United States is estimated to be 25%, in India to be 19% and in the Asian nations the rates of myopia are greater than 75%(1,2,3).

Studies have shown that complications from myopia, such as chorioretinal degeneration and retinal detachment will increase with increasing myopia. The application of corneal reshaping or orthokeratology may potentially stabilize the progressive nature of myopia throughout the adolescent years. Additionally, if wearing corneal reshaping lenses controls the progression of myopia, there also may be a reduction in the rates of adverse effects of advancing myopia. The fact that myopia is on the rise indicates that although the wearing of spectacles clears the vision, it does nothing to control the progression of myopia and its adverse effects.

Conclusions: The initial recruitment phase, fitting statistics, and demographics provide the structure for the five year SMART investigation. Initial dispensing data for corneal reshaping test subjects showed a high first lens success rate to achieve 20/20 unaided acuity. Long term results of this study will provide fitting information, myopia progression comparative data, anatomical differences, and subjective responses to each lens modality. 80.5% of the test group were fit able to use the initial empirically fit lens and did not require a lens change.

August 13, 2009- 11:45 am Naydi Olivera- I love this new website! I miss you guys so much! I just wanted to say that up to this point in my life, working there at AEC has been the best professional experience I have ever had. The management, the co-workers…Thank you for the chance to let me grow a little more. Hope things continue to go well for AEC. God Bless!-Naydi

July 21, 2009 - 8:31 pm Doctor Ben - Julia, I’m glad you brought this up. I’ve been fitting many post-LASIK patients into ortho-k the last several years for many different reasons. First of all, the reverse-geometry profile of the ortho-k lenses match the post-surgical shape of the cornea, which lends to better comfort and vision for daily wear. As a bonus, if the amount of regression from the surgery is minor, the lenses can be worn at night and removed in the morning like everyone else to enhance the LASIK back to the way it once was-or better! Another reason for the increase in the post-LASIK fittings is the fear of enhancement. A lot of patients don’t like the thought of doubling their surgical risks for a little tweak. Lastly, it provides more options for dealing with emerging presbyopia (the loss of near vision after age 40). As we age the prescription requirements for reading change. Ortho-K after LASIK allows for a gradual prescription change rather than overcorrecting a patient via a LASIK enhancement for how they will need to see a decade or more in the future.

July 21, 2009 - 5:44 pm Julia Goguen - I was wondering if someone has previously had laser surgery, but has now digressed to needing glasses again- would they be a possibility for Ortho-K? It is not me, but a relative…

July 16, 2009 - 2:09 pm Doctor Ben - Mr. Knott, I reviewed your file and you look like a great candidate for our new multifocal ortho-k design. It works pretty much the same as your current multifocal soft contacts, but you don’t have to worry about the occasional dryness. Due to the fact that you have some dryness issues with the soft lenses, I believe you should expect to see better with ortho-k. Whenever you add a material to the surface of your eye, more lubrication is needed no matter how good the material is. When you are seeing without a contact on your eye there is less lubrication needed and no dryness causing blurred vision. Overall everything should be better. Regarding your diabetes, there is no concern because there is no surgery or cutting. The tear film between the ortho-k lens and the cornea exerts a gentle pressure overnight that “molds” the cornea by only microns of change. A good analogy would be the indentation on your finger you get from your wedding band or any type of ring. The indentation is only temporary, goes away when you stop wearing your ring, and doesn’t cause harm to the health of your finger. See my other comments regarding dry eyes and ortho-k on a previous blog response today. Sincerely, Dr. Larson

July 16, 2009 - 1:47 pm Doctor Ben - Hi Wendy. Great question and a common concern with regular contacts. I myself have low-grade DES (dry eye syndrome). I also have large pupils to go along with DES so LASIK is a very poor option for me. I also had a very difficult time, even with all of the newer contact lens materials out there, finding one that didn’t dry out after several hours of wear. Ortho-K was the answer for me. I put them in before bed and take them out first thing in the morning and I’m dry eye free! One additional note on LASIK and DES. When the flap is created during the LASIK procedure, the nerve endings at the apex of the cornea are severed. These nerve endings are needed to stimulate the brain to stimuluate the glands of the eyes to secrete tears. When the stimulus is missing the bio-feedback loop is interrupted. This is why DES is often times a contraindication for LASIK. LASIK can still be successful, but usually after a few months of dry eye treatments.

July 16, 2009 - 1:32 pm Doctor Ben - Thanks Miss Douglas. The difference between soft contact lenses and ortho-k lenses is the gas permeability and size. Ortho-K lenses are similar, yet quite different than the hard lenses from a couple of decades ago also. They are made from hyper-dk (very gas permeable materials) and many curves can be “etched” into the material so as to customize the shape for each patient’s specific needs. They are also much smaller and very thin, yet very durable. Here are some pros/cons…. *Ortho-K lenses are safer: 1. more gas permeable, 2. worn only 6-8hrs/night, rather than 14-16hrs/day (or 24/7 for some patients), 3. less chance for exposure to environmental contaminants or infectious pathogens. *Ortho-K lenses are less expensive: See the Ortho-K cost analysis above. A pair of ortho-k lenses last 2 years and with a backup pair you get 4 years total. There are considerable discounts for all established ortho-k patients when new lenses/designs are needed. We will go over cost in detail when you come in for your annual appointment so that it is very clear. *Ortho-K lenses have to be worn on a night-time regimen of some sort. Some patients must wear them every night, some every other night and some every third night. That is a con for some, but for most a small price to pay for the convenience and ability to pursue new options in the future. Thanks again for posting your question and we look forward to seeing you soon! Sincerely, Dr. Larson

July 15, 2009 - 6:46 pm Terry Douglas - I am not really sure what the difference between regular contact lenses and Ortho-K lenses. I am still wearing glasses and have been considering contacts. I am a healthy 58 year old woman and just am not sure which direction to go. Can you post some of the pros and cons about the 2. Also, I am a little confused about the 4 year and 8 year price? Do the contacts last that long before you have to buy them again???? Hope you can help me understand a little better before I come in for my yearly appointment in a couple of weeks. Thanks

July 15, 2009 - 2:44 pm Wendy T. - My eyes are always dry with regular contacts how will my eyes not be dry when wearing Ortho lenses at night?

July 14, 2009 - 12:45 pm Bill K - I am currently a patient, I use Purevision mutlifocal lens pwr 1.0 high and 1.75 high. They work ok , but the dryness issue is anoying in the mornings and at the end of a day. I am an under control diabetic ( diet and pills) Am I candidate for Ortho-K ? Would one expect the results to be better or worse vision with it?

Ortho-K Cost Analysis

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