Spectacle lenses alter eye growth and the refractive status of young monkeys

Hung, Li-Fang; Crawford, Melba M.; Smith, Earl L.

doi:10.1038/nm0895-761

Cited by 402 publications

(281 citation statements)

References 23 publications

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“…[27][28][29][30][31][32][33] In particular, the negative-powered lenses imposed relative hyperopia on the treated eyes, which in response became more myopic than their fellow control eyes. In contrast, the positivepowered lenses imposed relative myopia, which initiated relative hyperopic shifts in the treated eye refractive errors.…”

Section: Refractive Development Is Regulated By Optical Defocusmentioning

confidence: 99%

Visual regulation of refractive development: insights from animal studies

Smith

Hung

Arumugam

2013

Eye

106

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Investigations employing animal models have demonstrated that ocular growth and refractive development are regulated by visual feedback. In particular, lens compensation experiments in which treatment lenses are used to manipulate the eye's effective refractive state have shown that emmetropization is actively regulated by signals produced by optical defocus. These observations in animals are significant because they indicate that it should be possible to use optical treatment strategies to influence refractive development in children, specifically to slow the rate of myopia progression. This review highlights some of the optical performance properties of the vision-dependent mechanisms that regulate refractive error development, especially those that are likely to influence the efficacy of optical treatment strategies for myopia. In this respect, the results from animal studies have been very consistent across species; however, to facilitate extrapolation to clinical settings, results are presented primarily for nonhuman primates. In agreement with preliminary clinical trials, the experimental data show that imposed myopic defocus can slow ocular growth and that treatment strategies that influence visual signals over a large area of the retina are likely to be most effective. Eye (2014) 28, 180-188; doi:10.1038/eye.2013.277; published online 13 December 2013Keywords: myopia; hyperopia; defocus; emmetropization Curtin 1 credits Kepler with being one of the first vision scientists to recognize the association between near work and myopia and for hypothesizing that myopia was an adaptation to near work. Although these seminal observations (circa 1610) have been replicated numerous times and much has been learnt about potential risk factors for the development of common forms of myopia, centuries of research on myopia in humans have failed to provide a clear indication of what it is about near work that promotes the development of myopia or to identify the physiological mechanisms that promote myopia in children as a result of chronic near work. However, beginning in the 1960s, research employing animal models was greatly expanded and began to provide new insights into the effects of visual experience on ocular growth and refractive development.The nature of the visual manipulations that have been employed to characterize refractive development in animals fall into three broad categories. The first category involved either natural or imposed restrictions in viewing distance and was largely motivated by the near work hypothesis. For example, comparisons of refractive errors between feral and domesticated or laboratory-reared animals supported the idea that environments that restrict viewing distance are myopiagenic. 2,3 However, these studies suffered from many of the same confounding issues associated with human studies. 4 A more controlled line of research was begun by Levinsohn 5 and continued most notably by Young, 6-9 who demonstrated that monkeys reared in environments with a maximum viewing distance o...

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Section: Refractive Development Is Regulated By Optical Defocusmentioning

confidence: 99%

Visual regulation of refractive development: insights from animal studies

Smith

Hung

Arumugam

2013

Eye

106

View full text Add to dashboard Cite

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“…This fact was unknown at the time of Helmholtz and thus there is no report that correlates a mechanism other. But today we know that both mechanisms are intimately linked (9)(10)(11)(12)(13) .…”

Section: The Mechanism Of the Ocular Emmetropizationmentioning

confidence: 99%

“…The classic experiments of Hung et al (12,13) , with placement of positive and negative lenses ("defocus" positive and negative, respectively) over the eyes of monkeys have shown that you can change the refractive state of eyes in minutes. Moreover, the posterior pole of younger eyes move with greater amplitude in the search for image focus, as shown in Figure 6.…”

Section: The Mechanism Of the Ocular Emmetropizationmentioning

confidence: 99%

New concepts in accommodation and presbyopia

Santos-Neto

Alves

2011

Rev. bras.oftalmol.

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The authors conducted a review of classical and conflicting theories of accommodation and presbyopia. They make a critical comparison with the findings of magnetic resonance imaging (MRI) that have been developed in recent decades. Based on these studies, formulates a new approach on the subject, shifting the focus of the discussion of the lens to the posterior pole of the eye.Keywords: Ocular accommodation ; Presbyopia RESUMOOs autores revisaram as teorias clássicas e conflitantes sobre acomodação e presbiopia. E as compararam criticamente com os achados de imagem por ressonância magnética (MRI) que têm se desenvolvido nas últimas décadas. Baseado nestes estudos, formulam uma nova abordagem sobre o tema, mudando o foco da discussão do cristalino para o polo posterior do olho.

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“…In a variety of young animals, ocular growth is modulated by the visual environment (Hung et al, 1995;Irving et al, 1992;Schaeffel et al, 1988;Siegwart and Norton, 1993;Wallman et al, 1978). This modulation process, called emmetropisation, has been studied experimentally with induced refractive errors; myopia can be induced by covering young eyes with diffusers (form deprivation) or negative lenses (imposed hyperopic defocus), and hyperopia can be induced by the addition of positive lenses (imposed myopic defocus).…”

Section: Introductionmentioning

confidence: 99%

Colchicine attenuates compensation to negative but not to positive lenses in young chicks

Choh

Padmanabhan

et al. 2008

Experimental Eye Research

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Optic nerve-sectioned (ONS) chick eyes are capable of emmetropisation, but these eyes also exhibit increased hyperopia without any visual manipulations, which suggests altered eye growth regulation. These altered growth changes may be related to the loss of retinal ganglion cells that follows nerve lesioning. Colchicine, which also destroys retinal ganglion cells in chicks, was used to further examine the effects of retinal ganglion cell loss on emmetropisation. Growth responses of +10 D and −10 D lens-wearing colchicine-injected eyes were compared to those of +10 D and −10 D lenswearing saline-injected eyes, respectively. Changes after removal of lenses were also analysed. Prior to lens-wear, colchicine-injected eyes exhibited longer optical axial lengths (OL; distance from cornea to retina; p=0.0185) but no differences in refractive error (RE; p=0.6588). Although myopic shifts were not significant for −10 D lens-wearing colchicine-injected eyes (p=0.5913), but were for the saline-injected eyes (p=0.0034), these changes were not different (p=0.1646). However, −10 D lens-induced OL changes in colchicine-injected eyes showed insignificant (p=0.2214) and reduced (p=0.0102) changes compared to those of saline-injected eyes. +10 D lens-treated colchicine-injected eyes showed significant hyperopic shifts (p<0.0001) and significant reductions in OL (p<0.0001) that were similar to those of saline-injected eyes (p=0.7990 and p=0.1495, respectively). Growth reponses in eyes recovering from −10 D lenses were minimal, with REs unaffected (p=0.3325), but OL reductions affected (p=0.0199) by colchicine. colchicine-injected eyes recovering from +10 D lenses showed significant myopic shifts (p=0.0003) and OL elongations (p<0.0001) that were similiar to those of saline-injected eyes (p=0.3999 and p=0.4731, respectively). The results showing that colchicine suppresses the ability to respond to negative lenses but leaves compensation to positive lenses relatively unchanged, are opposite to those of optic nerve sectioned eyes. We speculate that the differences are probably related to the way retinal cells are lost.

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Spectacle lenses alter eye growth and the refractive status of young monkeys

Cited by 402 publications

References 23 publications

Visual regulation of refractive development: insights from animal studies

Visual regulation of refractive development: insights from animal studies

New concepts in accommodation and presbyopia

Colchicine attenuates compensation to negative but not to positive lenses in young chicks

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