Contact Lens Spectrum Supplements

Special Edition 2017

Contact Lens Spectrum

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C O N T A C T L E N S S P E C T R U M S P E C I A L E D I T I O N 2 0 1 7 c l s p e c t r u m . c o m 66 PEDIA TRIC AND TEEN CL CARE M E L A N I E FR O G OZO, O D Dr. Frogozo specializes in adult and pediatric specialty contact lenses. She is the director of the Contact Lens Institute of San Antonio and the owner of Alamo Eye Care in San Antonio, Texas. She also is a consultant to CooperVision and Visionary Optics. You can contact her at contactlensinstitutesa@gmail.com. higher myopia. Preventing chil- dren from developing myopia and its associated visual impairments is, therefore, crucial. Effective Approaches Either preventing the onset or lim- iting the progression of myopia is con- sidered myopia control. Effective ap- proaches for limiting the progression include antimuscarinic agents, such as atropine, orthokeratology (ortho-k), and soft bifocal contact lenses (Wal- line, 2016). Nevertheless, all myopia control strategies are off-label. Myo- pia control with contact lenses is ac- complished by providing a myopic blur cue to the retina, which is as- Soft Bifocal Lenses: Soft bifocal contact lenses come in both center- distance and center-near designs. Most commercially available molded soft bifocal lenses are center-near designs, however, there are more myopia control studies using center distance bifocals. On average, soft bifocal contact lenses slow myopic progression by 46% (Walline, 2016). Other Contact Lens Options: GP lenses effectively correct high amounts of myopia and astigmatism. Bifocal GP lenses are, therefore, bet- ter suited for myopia control in chil- dren with high amounts of refractive error who are difficult to correct with ortho-k or soft bifocal lenses (Liu, 2017). Many corneal and scleral GP lenses are commercially available in bifocal designs. Hybrid lenses also are available with bifocal parameters. Summary The prevalence of myopia is in- creasing worldwide. High myopia is best prevented and myopia control offers a solution. Early intervention is best and contact lens based inter- ventions aim to create a peripheral defocus retinal cue that slows myo- pic progression. Management may involve ortho-k or bifocal contact lenses including soft or GP varieties as the situation warrants. CLS For references, please visit www. clspectrum.com/references and click on document #SE2017. sumed to act as a retinal cue to slow myopic eye growth (Walline, 2016). Orthokeratology: Ortho-k uses GP lenses worn overnight to temporar- ily reshape the cornea to correct for refractive error during waking hours (Figure 1). Myopic orthokeratology shifts the cornea from its normal pro- late aspheric shape toward an oblate asphere (Rinehart, 2006) (Figure 2). When reshaped, the central apex is flatter than the midperipheral cornea creating the needed distance correc- tion and the peripheral defocus cue. On average, ortho-k slows myopic progression by 43% (Walline, 2016). MYOPIA CONTROL M yopia is the most common eye disorder in the world. It is estimated that 4.8 billion people (49.8% of the world's population) will be myopic by 2050 (Holden et al, 2016). Developed Asian countries are particularly affected. For example, in Singapore and Taiwan, up to 84% of school-aged children are myopic (Wu et al, 2016). In contrast, but still of concern, about 50% of adults in the United States and Europe are myopic. High myopia is a leading cause of blindness and is associated with comorbidities, such as retinal detachment, macular choroidal degen- eration, premature cataract, and glaucoma (Cho et al, 2016). Pediatric onset is most troublesome since this leaves more time for progression to Figure 1. Orthokeratology gas permeable lens on eye. On average, orthokeratology slows myopic progression by 43%. Figure 2. Orthokeratology lenses flatten the central apex and steepen the midperipheral cornea, thus creating the needed distance correc- tion and also the peripheral retinal defocus cue for myopia control.

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