Orthokeratology
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Orthokeratology
Orthokeratology is a clinical technique that uses specially designed and fitted rigid contact lenses to reshape the corneal contour to temporarily modify or eliminate refractive error. Modern orthokeratology using reverse-geometry gas-permeable lenses is an effective procedure for the reversible vision correction. The use of an overnight lens-wearing protocol provides an alternative to refractive surgery for many patients.
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Long-term Efficacy of Orthokeratology Contact Lens Wear in Controlling the Progression of Childhood Myopia

Long-term Efficacy of Orthokeratology Contact Lens Wear in Controlling the Progression of Childhood Myopia | Orthokeratology | Scoop.it

The primary outcome of this study is to compare the axial length growth of white European myopic children wearing orthokeratology contact lenses (OK) to a control group (CT) over a 7-year period. A trend toward a reduction in the rate of axial elongation of the order of 33% was found in the OK group in comparison to the CT group following 7 years of lens wear.

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Ortho-K lenses should not increase microbial keratitis risk

Purpose: To investigate normal flora of children with and without orthokeratology (ortho-k) treatment, and the associations between carriage of Staphylococcus aureus and Gram-negative rods with contamination of contact lenses and lens cases in ortho-k subjects and with spectacles of control subjects. Methods: Twenty-three ortho-k subjects (treatment >12 months) and 20 control myopic subjects aged 7–14 years were recruited. Samples were collected from four sites surrounding the left eye (lower conjunctiva, upper and lower eyelids, and eyelashes) for all subjects, spectacles for control subjects and contact lens accessories for ortho-k subjects. Samples were cultured, total numbers enumerated, and isolates identified using chromogenic agars. Results: Ortho-k subjects had significantly less total isolates in the conjunctiva than controls (p = 0.009). Otherwise, carriage rates in normal flora levels of the peri-orbital tissues were not significantly different between the two groups (p > 0.19). The total isolates and carriage rates of normal flora on spectacles, contact lenses, and lens cases were similar to those identified on the skin tissues. Small numbers of bacteria were identified from the multipurpose solution of two ortho-k subjects. Although the association between the carriage of S. aureus with contamination of accessories was statistically significant only in control subjects (p = 0.03), ortho-k subjects not yielding S. aureus and Gram-negative rods from samples of their peri-orbital tissues tended to be less likely to have these organisms in their accessories. No Pseudomonas was isolated from any of the sites sampled and no Acinetobacter was isolated from any of the accessories. 

Conclusions: Ortho-k may lower the total number of bacteria in conjunctiva due to the use of solution and lenses, but the physiologic effect of this treatment on the types of normal flora in children was minimal and should not increase the risk of microbial keratitis in children with good compliance.


Cheung SW, Boost M, Shi GS, Cho P. Microbial Contamination of Periorbital Tissues and Accessories of Children. Optom Vis Sci. 2016 Jun;93(6):612-8.

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Controlling myopia progression in children and adolescents

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"Orthokeratology contact lenses slow axial length growth compared to single vision gas permeable contact lenses,96 single vision soft contact lenses, and single vision spectacles. The first randomized clinical trial of orthokeratology myopia control demonstrated significantly slower mean (± standard deviation) axial elongation in children wearing orthokeratology lenses (0.36±0.24 mm) than children wearing single vision spectacles (0.63±0.26 mm, P<0.01)."

Smith MJ, Walline JJ. Controlling myopia progression in children and adolescents. Adolesc Health Med Ther. 2015 Aug 13;6:133-40

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Myopia Control with a Novel Peripheral Gradient Soft Lens and Orthokeratology: A 2-Year Clinical Trial

"Objective. To evaluate the degree of axial elongation with soft radial refractive gradient (SRRG) contact lenses, orthokeratology (OK), and single vision (SV) spectacle lenses (control) during a period of 1 year before treatment and 2 years after treatment. Results. After 2 years, the mean myopia progression values for the SRRG, OK, and SV groups were −0.56 ± 0.51, −0.32 ± 0.53, and −0.98 ± 0.58 diopter, respectively. The results represent reductions in myopic progression of 43% and 67% for the SRRG and OK groups, respectively, compared to the SV group. The AL increased 27% and 38% less in the SRRG and OK groups, respectively compared with the SV group at the 2-year visit (P < 0.05). Axial elongation was not significantly different between SRRG and OK (P = 0.430)." 

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Efficacy and Acceptability of Orthokeratology for Slowing Myopic Progression in Children: A Systematic Review and Meta-Analysis

Eight studies involving 769 subjects were included. At 2-year follow-up, a statistically significant difference was observed in axial length change between the orthokeratology and control groups, with a weighted mean difference (WMD) of −0.25 mm (95% CI, −0.30 to −0.21). The pooled myopic control rate declined with time, with 55, 51, 51, and 41% obtained after 6, 12, 18, and 24 months of treatment, respectively. No statistically significant difference was obtained for dropout rates between the orthokeratology and control groups at 2-year follow-up (OR, 0.79; 95% CI, 0.52 to 1.22). Conclusions. Orthokeratology is effective and acceptable for slowing myopic progression in children with careful education and monitoring.

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http://downloads.hindawi.com/journals/joph/2015/360806.pdf

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Strategies to Regulate Myopia Progression With Contact Lenses: A Review.

Strategies to Regulate Myopia Progression With Contact Lenses: A Review. | Orthokeratology | Scoop.it

"Contact lenses were reported to be well accepted, consistent, and safe methods to address myopia regulation in children. Orthokeratology is so far the method with the largest demonstrated efficacy in myopia regulation across different ethnic groups." 

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Influence of Ocular Wavefront Aberrations on Axial Length Elongation in Myopic Children Treated with Overnight Orthokeratology - Ophthalmology

Influence of Ocular Wavefront Aberrations on Axial Length Elongation in Myopic Children Treated with Overnight Orthokeratology - Ophthalmology | Orthokeratology | Scoop.it

"Asymmetric corneal shapes, rather than concentric and radially symmetric shapes, have a considerable effect on retardation of axial elongation, suggesting that the inhibitory effect of orthokeratology on myopia progression is caused by mechanisms other than the reduction in peripheral hyperopic defocus" 

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Abraham Zlatin, O.D., F.O.A.A.'s curator insight, January 27, 2015 2:03 PM

An optical method for controlling the abnormal growth of the eye has beven discovered.

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Orthokeratology for Myopia Control: A Meta-analysis. : Optometry & Vision Science

The major purpose of the present meta-analysis was to evaluate the efficacy of orthokeratology in myopia control. This meta- analysis suggests that compared with control, orthokeratology may effectively reduce the elongation of AL to a certain extent, with mean differences of -0.26 mm in 2 years. Moreover, the difference between orthokeratology and control in VCD elongation was -0.18 mm in 2 years. Exclusion of any single study and sensitivity analysis based on various exclusion criteria did not materially alter the pooled results, which added robustness to this main result.

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Myopia Control during Orthokeratology Lens Wear in Children Using a Novel Study Design - Ophthalmology

Myopia Control during Orthokeratology Lens Wear in Children Using a Novel Study Design - Ophthalmology | Orthokeratology | Scoop.it

A prospective, randomized, contralateral-eye crossover study conducted over a 1-year period. The results provide evidence that, at least in the initial months of lens wear, overnight OK inhibits axial eye growth and myopia progression compared with conventional GP lenses.

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Seven-year retrospective analysis of the myopic control effect of orthokeratology in children

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Myopia control: the time is now

Myopia control: the time is now | Orthokeratology | Scoop.it

Ophthalmic and Physiological Optics

Volume 34, Issue 3, pages 263–266, May 2014

 

Antonio Calossi's insight:

"Modern overnight corneal reshaping or orthokeratology (Ortho-K) is effective for temporary myopic reduction and there was anecdotal evidence that these lenses may slow myopia progression in children."

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Orthokeratology: An Update

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Campbell and There (Karrinyup, Western Australia) report that at present, orthokeratology stands as being the most effective mode of myopia control. The purpose of this paper is to review the literature involving orthokeratology treatment since 2006. 

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AEOPTOMETRISTAS's curator insight, March 11, 2014 1:49 AM
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Campbell  y colaboradores (Karrinyup, Australia Occidental) informan que en la actualidad, la ortoqueratología destaca por ser el modo más eficaz de control de la miopía. El propósito de este trabajo es revisar la literatura que implica el tratamiento de ortoqueratología desde 2006. 

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Myopia Control in Children through Refractive Therapy Gas Permeable Contact Lenses: Is it for Real?

Myopia Control in Children through Refractive Therapy Gas Permeable Contact Lenses: Is it for Real? | Orthokeratology | Scoop.it

The December issue of the American Journal of Ophthalmology compares the safety and efficacy of orthokeratology as a nonsurgical treatment for myopia in children with alternate methods.

In all of the studies reviewed, the use of orthokeratology lenses proved to reduce myopia, to improve visual acuity, and to reduce the rate of axial elongation. Orthokeratology has been shown to be as effective as other methods in treating myopia and to be more effective at treating axial elongation. There were no major adverse events in any of the studies comparing orthokeratology with other methods of myopia treatment.

In conclusion, studies show that the use of orthokeratology is a safe and efficacious nonsurgical treatment for myopia and that it is capable of slowing axial elongation, making it an effective myopic treatment for children.

 
American Journal of Ophthalmology, Volume 156, Issue 6, Pages 1076-1081.e1, December 2013, Authors:Bruce H. Koffler; James J. Sears
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Effects of orthokeratology on the progression of low to moderate myopia in Chinese children

Effects of orthokeratology on the progression of low to moderate myopia in Chinese children | Orthokeratology | Scoop.it

"The current study confirms that the ortho-k lens is a promising treatment method to control myopia in children with low to moderate myopia. In particular,this lens offers more benefits to younger children with fast progression and allows better control of higher degrees of myopia. Although the ortho-k lens cannot completely arrest axial elongation in myopic children, it can retard it to a certain extent, which suggests that this treatment is a good choice for myopic children for whom wearing the ortho-k lens is suitable."

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Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050 - Ophthalmology

By the year 2050, nearly half of the planet will suffer from some degree of myopia. One fifth of them will be at increased risk for total, permanent blindness. This is according to this study published in the journal Ophthalmology by researchers at the Brien Holden Vision Institute. "Our systematic review, meta-analysis, and projections provide myopia and high myopia predictions through 2050 and their distribution between GBD regions. Our estimates and projections assimilate local, individual studies into an improved global understanding of myopia epidemiologic factors. Our methodology provides a basis for validation of projections against new evidence as it is published. If correct, our projections have significant implications for planning comprehensive eye care services globally, which would need to cater to close to 1 billion people with high myopia by 2050, 7.5 times more than in 2000. The benefits of a multifaceted myopia control system to buffer this scenario would be substantial." The authors said
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The Safety of Orthokeratology: A Systematic Review

The aim of this review is to evaluate the ocular safety of orthokeratology (OrthoK) treatment of myopia correction and retardation.

Data Sources: Clinical studies published in English and Chinese were identified from MEDLINE, EMBASE CNKI, CQVIP, and WANFANG DATA (all from 1980 to April 2015). The reference lists of the studies and the Science Citation Index were also searched.

Selection Criteria: Relevant clinical studies including case series, case reports, patient/practitioner surveys, retrospective and prospective cohort studies, and clinical trials were all included in the review. The material of OrthoK lenses was limited to gas-permeable lens.

Main Results: This review incorporated a total of 170 publications, including 58 English and 112 Chinese literature. The risk of microbial keratitis in overnight OrthoK was similar to that of other overnight modality. The most common complication was corneal staining. Other clinically insignificant side effects included epithelial iron deposit, prominent fribrillary lines, and transient changes of corneal biomechanical properties. There was no long-term effect of OrthoK on corneal endothelium.

Conclusions: There is sufficient evidence to suggest that OrthoK is a safe option for myopia correction and retardation. Long-term success of OrthoK treatment requires a combination of proper lens fitting, rigorous compliance to lens care regimen, good adherence to routine follow-ups, and timely treatment of complications.

Liu et al. Eye & Contact Lens: Science & Clinical Practice:

January 2016 - Volume 42 - Issue 1 - p 35–42

 

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Efficacy, Safety and Acceptability of Orthokeratology on Slowing Axial Elongation in Myopic Children by Meta-Analysis

Efficacy, Safety and Acceptability of Orthokeratology on Slowing Axial Elongation in Myopic Children by Meta-Analysis | Orthokeratology | Scoop.it

Orthokeratology has significantly greater efficacy in controlling axial elongation in children compared to Spectacle correction. The safety and acceptability results are good, and there appears to be a greater myopia control effect in Chinese children compared to Caucasians, and in those with higher initial myopia.

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Fluorophotometry to Evaluate the Corneal Epithelium in Eyes Undergoing Contact Lens Corneal Reshaping to Correct Myopia | Journal of Refractive Surgery

Fluorophotometry to Evaluate the Corneal Epithelium in Eyes Undergoing Contact Lens Corneal Reshaping to Correct Myopia | Journal of Refractive Surgery | Orthokeratology | Scoop.it
PURPOSE To determine whether use of orthokeratology lenses have an adverse effect on the health of corneal epithelium by monitoring epithelial permeability by fluorophotometry.
CONCLUSIONS Reshaping of the cornea through the use of orthokeratology does not have adverse effects on corneal epithelium as evaluated by changes in corneal epithelial permeability.
[J Refract Surg. 2009;25:366-370.]
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Orthokeratology to Control Myopia Progression: A Meta-Analysis

Orthokeratology to Control Myopia Progression: A Meta-Analysis | Orthokeratology | Scoop.it
Objective To evaluate the clinical treatment effects of orthokeratology to slow the progression of myopia. Methods Several well-designed controlled studies have investigated the effects of orthokeratology in school-aged children. We conducted this meta-analysis to better evaluate the existing evidence. Relevant studies were identified in the Medline and Embase database without language limitations. The main outcomes included axial length and vitreous chamber depth reported as the mean ± standard deviation. The results were pooled and assessed with a fixed-effects model analysis. Subgroup analyses were performed according to geographical location and study design. Results Of the seven eligible studies, all reported axial length changes after 2 years, while two studies reported vitreous chamber depth changes. The pooled estimates indicated that change in axial length in the ortho-k group was 0.27 mm (95% confidence interval [CI]: 0.22, 0.32) less than the control group. Myopic progression was reduced by approximately 45%. The combined results revealed that the difference in vitreous chamber depth between the two groups was 0.22 mm (95% confidence interval [CI]: 0.14, 0.31). None of the studies reported severe adverse events. Conclusion The overall findings suggest that ortho-k can slow myopia progression in school-aged children.
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AEOPTOMETRISTAS's curator insight, April 14, 2015 12:39 AM

Los resultados generales sugieren que la orto-k puede ralentizar la progresión de la miopía en los niños en edad escolar.

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The control effect of orthokeratology on axial length elongation in Chinese children with myopia

The control effect of orthokeratology on axial length elongation in Chinese children with myopia | Orthokeratology | Scoop.it

This 2-year study indicates that ortho-k contact lens wear is effective for reducing myopia progression in children with low, moderate and high myopia.

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UpTempo Group's curator insight, March 2, 2015 1:35 PM

A retrospective study conducted by researchers in China evaluated the effectiveness of Orthokeratology, (Ortho-K) in treating myopia for children between the ages of 7 and 14.  These children had no other ocular problems outside of myopia. 


The study concludes that Orthokeratology is a promising treatment for children with myopia as compared to spectacles.  The study also concludes that the early treatment of myopia may reduce the prevalence of high myopia. Another conclusion is that orthokeratology may be most beneficial for younger children.   


Studies looking into myopia are very important as this paper suggests. Per this article, the World Health Organization's Vision 2020 initiative ranks the treatment of myopia as one of the top 5 vision priorities.  Although Myopia may not be as debilitating as cataracts, there are concerns that the early age of onset of Myopia may have a much more significant effect due to the total lifetime burden of the disease.


The study recommends early treatment of myopia to reduce the progression of myopia and  to protect the quality of life for patients as they age. 

 


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"Spherical aberration, accommodation and myopia" PhD Thesis by Janice Marie Tarrant

"The hypothesis that hyperopic defocus from under-accommodation during near work is the driving stimulus in the progression of myopia, motivated studies of bifocal spectacles and progressive addition lenses, as optical treatments for the control of myopia progression, with limited success. In contrast, multifocal (MF) soft contact lenses (SCL) and orthokeratology (ortho-k) have proven to be more beneficial although the mechanisms underlying their anti-myopia effects are not understood. This dissertation, which describes 4 main studies, represents efforts to understand how spherical aberration influences the accommodative response and examines as an explanation for the myopia control effects of MF SCLs and ortho-k the possibility that induced changes in ocular spherical aberration decreases the lag of accommodation."

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BMC Ophthalmology | Abstract | The control effect of orthokeratology on axial length elongation in Chinese children with myopia

" This 2-year study indicates that ortho-k contact lens wear is effective for reducing myopia progression in children with low, moderate and high myopia"

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Prentice Award Lecture 2010: A Case for Peripheral Optical Treatment Strategies for Myopi Smith, Earl L. III*

Prentice Award Lecture 2010: A Case for Peripheral Optical Treatment Strategies for Myopi Smith, Earl L. III* | Orthokeratology | Scoop.it
It is well established that refractive development is regulated by visual feedback. However, most optical treatment strategies designed to reduce myopia progression have not produced the desired results, primarily because some of our assumptions concerning the operating characteristics of the vis...
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Overnight orthokeratology is comparable with atropine in controlling myopia

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Justin Bazan's curator insight, April 3, 2014 8:17 AM

Wish you could stop your prescription from going up every year?!?!?! YOU CAN! Here are 2 proven ways to do so.

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The Case for Myopia Control Now | Refractive Eyecare

The Case for Myopia Control Now | Refractive Eyecare | Orthokeratology | Scoop.it

Interesting article at www.refractiveeyecare.com! Refractive Eyecare provides clear, clinical, and comprehensive information for improving both patient outcomes and bottom-line results.

 "Myopia prevalence is increasing rapidly around the world. East Asia is the most affected region, but rapidly rising rates of myopia can be found throughout the developed world. Research in animal models has shown that axial elongation can be triggered by hyperopic blur in the peripheral retina. The explosion of near-vision tasks to which children have been subjected in developed countries is thought to be behind the rising rates of myopia. Both drugs and overnight orthokeratology have been shown effective in slowing myopia progression in children. Among the demonstrated safety and efficacy, there are many good reasons for ophthalmologists to consider adopting orthokeratology in their practices" doctor Bruce H. Koffler said.


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