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E. L. Smith, III, L.-F. Hung, R. Ramamirtham, J. Huang, Y. Qiao-Grider; Optically Imposed Hyperopic Defocus in the Periphery Can Produce Central Axial Myopia in Infant Monkeys. Invest. Ophthalmol. Vis. Sci. 2007;48(13):1533.
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Several lines of evidence suggest that vision-initiated signals in the peripheral retina can influence central refractive development. The purpose of this study was to determine whether optically imposed hyperopic defocus in the periphery, like selective peripheral form deprivation, can produce central axial myopia in developing primates.
Relative peripheral hyperopia was produced in both eyes of 8 infant monkeys by rearing them with -3.0 D spectacle lenses that had 6 mm apertures centered on the pupils of each eye to allow 30 degrees of unrestricted central vision. The effects of the rearing procedure on refractive development were assessed by retinoscopy, keratometry, and A-scan ultrasonography performed along the pupillary axis. Comparison data were obtained from 6 infants that wore intact -3.0 D spectacle lenses that imposed relative hyperopia across the entire field of view of both eyes. Control Data on normal refractive development were obtained from 21 normal monkeys and 3 infants reared with binocular plano lenses.
At the end of the lens rearing, 4 of the 8 treated monkeys that were reared with relative peripheral hyperopic defocus exhibited absolute myopic refractive errors along the pupillary axis and the mean refractive error for the treated group was significantly less hyperopic than that for the control animals (+0.37 ± 2.31 D vs +2.69 ± 0.92 D; P = 0.04). The mean refractive error for the experimental animals that wore the intact negative lenses was approximately 1 D more myopic (-0.68 ± 1.82 D; P = 0.37) than that for animals that experienced selective peripheral hyperopic defocus.
The overall pattern of results indicate that both central and peripheral visual signals contribute to vision-dependent changes in axial growth. However, in terms of overall axial growth, visual signals from the periphery can dominate conflicting visual signals from the central retina.
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