Peripheral Vision Can Influence Eye Growth and Refractive Development in Infant Monkeys

College of Optometry, University of Houston, TX 77204, USA.
Investigative Ophthalmology & Visual Science (Impact Factor: 3.4). 12/2005; 46(11):3965-72. DOI: 10.1167/iovs.05-0445
Source: PubMed


Given the prominence of central vision in humans, it has been assumed that visual signals from the fovea dominate emmetropization. The purpose of this study was to examine the impact of peripheral vision on emmetropization.
Bilateral, peripheral form deprivation was produced in 12 infant monkeys by rearing them with diffusers that had either 4- or 8-mm apertures centered on the pupils of each eye, to allow 24 degrees or 37 degrees of unrestricted central vision, respectively. At the end of the lens-rearing period, an argon laser was used to ablate the fovea in one eye of each of seven monkeys. Subsequently, all the animals were allowed unrestricted vision. Refractive error and axial dimensions were measured along the pupillary axis by retinoscopy and A-scan ultrasonography, respectively. Control data were obtained from 21 normal monkeys and 3 infants reared with binocular plano lenses.
Nine of the 12 treated monkeys had refractive errors that fell outside the 10th- and 90th-percentile limits for the age-matched control subjects, and the average refractive error for the treated animals was more variable and significantly less hyperopic/more myopic (+0.03 +/- 2.39 D vs. +2.39 +/- 0.92 D). The refractive changes were symmetric in the two eyes of a given animal and axial in nature. After lens removal, all the treated monkeys recovered from the induced refractive errors. No interocular differences in the recovery process were observed in the animals with monocular foveal lesions.
On the one hand, the peripheral retina can contribute to emmetropizing responses and to ametropias produced by an abnormal visual experience. On the other hand, unrestricted central vision is not sufficient to ensure normal refractive development, and the fovea is not essential for emmetropizing responses.

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Available from: Chea-Su Kee, Mar 25, 2014
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    • "Improvements in accommodation performance, i.e., reduced lags, have also been reported with orthokeratology [31], lending further support to the notion that reduction or elimination of accommodative lags contributes to the myopia control effects of such treatments. The notion that the peripheral retina plays a critical role in refractive error development and thus in myopia progression also has its origins in animal model studies [32] [33] [34] [35] [36] and is driving the development of some novel designs of spectacles [7] [8] and soft contact lenses (SCLs) [9] [10] [11] for myopia control. The underlying premise is that by manipulating the defocus experience of the peripheral retina, one can either neutralise the optical defocus stimulus for excessive axial length elongation, i.e., by correcting peripheral (off-axis) hyperopia, or reverse it by imposing myopic defocus, thereby inhibiting eye growth. "
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    • "This is especially true in relation to the amount of refractive error that is related to an increased risk of retinal detachment, glaucoma, cataract, and chorioretinal degeneration as the leading causes of permanent visual impairment [2]. Studies of the emmetropization mechanism in animals have suggested that treatments that consider the peripheral retina may be much more effective than others [3]. In particular , experiments in monkeys have indicated that visual signals from the peripheral retina are essential for several aspects of regulation of vision-dependent ocular growth [4]. "
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