Effectiveness of Orthokeratology in Myopia Control
| Status: | Recruiting |
|---|---|
| Conditions: | Ocular |
| Therapuetic Areas: | Ophthalmology |
| Healthy: | No |
| Age Range: | 6 - 13 |
| Updated: | 4/17/2018 |
| Start Date: | May 1, 2017 |
| End Date: | May 2019 |
| Contact: | Jennifer Harthan, OD |
| Email: | JHarthan@ico.edu |
| Phone: | 312-949-7137 |
The high prevalence of myopia - especially in Asian countries - is well documented, as are
the sight-threatening complications of high or degenerative myopia. Retinal detachment,
glaucoma, vitreal degeneration and focal retinal changes may occur secondary to the
progressive axial elongation of the eye with age. Specialty rigid lenses have long been shown
to lessen this progression in the pediatric population; orthokeratology (ortho-k) lenses are
worn at night and change the corneal topography to correct low to moderate amounts of myopia.
Most of the studies on orthokeratology were conducted on Asian children. To the best of the
investigators knowledge, no study has been done on African American (AA) children. The
investigators' project seeks to investigate the efficacy of ortho-k in slowing axial
elongation and myopic progression in AA children compared to that in other races.
the sight-threatening complications of high or degenerative myopia. Retinal detachment,
glaucoma, vitreal degeneration and focal retinal changes may occur secondary to the
progressive axial elongation of the eye with age. Specialty rigid lenses have long been shown
to lessen this progression in the pediatric population; orthokeratology (ortho-k) lenses are
worn at night and change the corneal topography to correct low to moderate amounts of myopia.
Most of the studies on orthokeratology were conducted on Asian children. To the best of the
investigators knowledge, no study has been done on African American (AA) children. The
investigators' project seeks to investigate the efficacy of ortho-k in slowing axial
elongation and myopic progression in AA children compared to that in other races.
Orthokeratology (ortho-k), when used for partial or full correction of myopia, has been shown
to slow myopic progression in children by 36-56% as compared to their spectacle or
contact-lens wearing peers.1 This effect is achieved by limiting the axial elongation of the
eye,1, 2,3, 4 which is of particular concern in high myopes (>6.00D) and children, where
myopic progression has been shown to proceed at a faster rate than average.1 As early
intervention is considered beneficial if not essential, Ortho-k as a treatment modality for
diminishing myopic progression has, to our knowledge, been studied mostly in Asian children.
The safety and efficacy of ortho-k as a means of decreasing myopic progression was well
established by the Children's Overnight Orthokeratology Investigation (COOKI), who evaluated
refractive error, visual changes and ocular health over a period of 6 months in myopic
children. 7 The Longitudinal Orthokeratology Research in Children (LORIC) study looked at
axial elongation in children as old as 12 years, and found that ortho-k decreased axial
elongation by approximately 50% compared to be-spectacled controls. 2 They also noted,
however, high variability amongst the children that limits the clinician's ability to predict
the outcome of the intervention.2 The Corneal Reshaping and Yearly Observation of Myopia
(CRAYON) study confirmed that patients fit with ortho-k lenses showed less change in axial
length and vitreous chamber depth when compared to subjects wearing soft contact lenses. 3
Other more recent studies by Santodomingo-Rubido et al, 7 Kakita et al4 and Charm et al1
confirm this decrease in axial elongation using IOL Master measurements.
The most commonly accepted theory on how orthokeratology decreases axial elongation relies on
the peripheral defocus created on the retina by the corneal changes made by the rigid lens. 9
Hoogerheide et al showed that those at greatest risk for myopic progression were those whose
peripheral refraction was hypermetropic10 - that is, they had a hyperopic peripheral
'defocus'. A number of studies have since suggested that treatment approaches to myopia
correction should address this peripheral refraction as a means of slowing further axial
elongation.9 When looking at subjects treated with ortho k, we see that the lenses do in fact
introduce a peripheral myopic defocus while leaving the central refraction more or less
emmetropic. 9 With this study, the investigators hope to expand potential application of
orthokeratology to a novel population, AA children.
to slow myopic progression in children by 36-56% as compared to their spectacle or
contact-lens wearing peers.1 This effect is achieved by limiting the axial elongation of the
eye,1, 2,3, 4 which is of particular concern in high myopes (>6.00D) and children, where
myopic progression has been shown to proceed at a faster rate than average.1 As early
intervention is considered beneficial if not essential, Ortho-k as a treatment modality for
diminishing myopic progression has, to our knowledge, been studied mostly in Asian children.
The safety and efficacy of ortho-k as a means of decreasing myopic progression was well
established by the Children's Overnight Orthokeratology Investigation (COOKI), who evaluated
refractive error, visual changes and ocular health over a period of 6 months in myopic
children. 7 The Longitudinal Orthokeratology Research in Children (LORIC) study looked at
axial elongation in children as old as 12 years, and found that ortho-k decreased axial
elongation by approximately 50% compared to be-spectacled controls. 2 They also noted,
however, high variability amongst the children that limits the clinician's ability to predict
the outcome of the intervention.2 The Corneal Reshaping and Yearly Observation of Myopia
(CRAYON) study confirmed that patients fit with ortho-k lenses showed less change in axial
length and vitreous chamber depth when compared to subjects wearing soft contact lenses. 3
Other more recent studies by Santodomingo-Rubido et al, 7 Kakita et al4 and Charm et al1
confirm this decrease in axial elongation using IOL Master measurements.
The most commonly accepted theory on how orthokeratology decreases axial elongation relies on
the peripheral defocus created on the retina by the corneal changes made by the rigid lens. 9
Hoogerheide et al showed that those at greatest risk for myopic progression were those whose
peripheral refraction was hypermetropic10 - that is, they had a hyperopic peripheral
'defocus'. A number of studies have since suggested that treatment approaches to myopia
correction should address this peripheral refraction as a means of slowing further axial
elongation.9 When looking at subjects treated with ortho k, we see that the lenses do in fact
introduce a peripheral myopic defocus while leaving the central refraction more or less
emmetropic. 9 With this study, the investigators hope to expand potential application of
orthokeratology to a novel population, AA children.
Inclusion Criteria:
- myopia progression more than -1.00D in one year
- myopic prescription between -1.00D and -6.00D in at least one eye with refractive
astigmatism <1.50D
- Best corrected VA 20/25 or better
- subjects willing to present to clinic for all necessary follow up care
- willing to be randomized to either group
Exclusion Criteria:
- non-compliance with treatment protocol
- contraindications for orthok as per company guidelines
- history of refractive surgery
- current gas permeable contact lens wearers
We found this trial at
1
site
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