Effects of spectacle intervention on the progression of myopia in children

The literature on myopigenesis suggests an active emmetropization mechanism regulated by optical defocus. The strongest evidence comes from compensato ry ocular growth in response to lens-induced defocus in different species o f animals. Based on these results, it has been suggested that, however usef ul, spectacle intervention for the optical correction of human myopia would lead to its exacerbation. The present study seeks to evaluate the progress ion of juvenile-onset myopia in children differentiated by their lens wear patterns. Data from 43 myopes from our longitudinal study of refraction wer e evaluated, with myopia defined as a spherical equivalent of at least -0.5 0 D. Refractions were obtained in the laboratory by noncycloplegic retinosc opy performed by one experienced optometrist at regular intervals. informat ion regarding the subjects' prescription lens-wearing history was obtained from the subjects and their eye cave providers. Based on their wearing patt erns, subjects were divided into four categories: (1) full-time wearers; (2 ) myopes who switched from distance to full-time wear; (3) distance wearers ; and (4) nonwearers. Exponential functions were fit to the individual refr action data. The age of onset of myopia, the mean myopia at onset of specta cle wear, and the refractive shift over a period of at least 3 years were d erived from these fits. Results show that the 3-year refractive shifts are not significantly different among the four groups. A comparison of the extr eme conditions, i.e., full-time vs, nonwear categories;, also revealed no s ignificant difference when the data were corrected for age effects despite the fact that the nonwearers exhibited an age-adjusted 3-year progression a pproximately one-half that of the full-time wearers. In summary, the presen t study failed to demonstrate any overall effects of spectacle intervention on the progression of human myopia. Further investigation using a larger s ample is warranted.