The Effect of Simultaneous Negative and Positive Defocus on Eye Growth and Development of Refractive State in Marmosets

Benavente-Perez, Alexandra; Nour, Ann; Troilo, David

doi:10.1167/iovs.12-9822

Cited by 89 publications

(115 citation statements)

References 37 publications

(62 reference statements)

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“…It has been shown that presenting chick eyes with simultaneously competing myopic and hyperopic defocus, using either mixed astigmatic (toric) lenses with opposite lens powers on the two perpendicular meridians (McLean and Wallman 2003), lens-cone devices with two target planes (Diether and Wildsoet 2005) or dual-power lenses that had different combinations of lens powers (Tse et al 2007), caused hyperopia, confirming the dominating effect of myopic defocus in chicks. Moreover, Benavente-Perez et al (2012) reported similar results in marmosets by using multi-zone contact lenses with alternating powers. Therefore, it seems that when the retina experiences myopic and hyperopic defocus simultaneously, myopic defocus still dominates compensation, although to a smaller degree than when the eye experiences myopic and hyperopic defocus in succession.…”

Section: Integration Of Simultaneous Myopic and Hyperopic Defocusmentioning

confidence: 55%

Temporal integration of visual signals in lens compensation (a review)

Zhu

2013

Experimental Eye Research

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Postnatal eye growth is controlled by visual signals. When wearing a positive lens that causes images to be focused in front of the retina (myopic defocus), the eye reduces its rate of ocular elongation and increases choroidal thickness to move the retina forward to meet the focal plane of the eye. When wearing a negative lens that causes images to be focused behind the retina (hyperopic defocus), the opposite happens. This review summarizes how the retina integrates the constantly changing visual signals in a non-linear fashion to guide eye growth in chicks: (1a) When myopic or hyperopic defocus is interrupted by a daily episode of normal vision, normal vision is more effective in reducing myopia caused by hyperopic defocus than in reducing hyperopia caused by myopic defocus; (1b) when the eye experiences alternating myopic and hyperopic defocus, the eye is more sensitive to myopic defocus than to hyperopic defocus and tends to develop hyperopia, even if the duration of hyperopic defocus is much longer than the duration of myopic defocus; (2) when the eye experiences brief, repeated episodes of defocus by wearing either positive or negative lenses, lens compensation depends on the frequency and duration of individual episodes of lens wear, not just the total daily duration of lens wear; and (3) further analysis of the time constants for the hypothesized internal emmetropization signals show that, while it takes approximately the same amount of time for the signals to rise and saturate during lens-wearing episodes, the decline of the signals between episodes depends strongly on the sign of defocus and the ocular component. Although most extensively studied in chicks, the nonlinear temporal integration of visual signals has been found in other animal models. These findings may help explain the complex etiology of myopia in school-aged children and suggest ways to slow down myopia progression.

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Section: Integration Of Simultaneous Myopic and Hyperopic Defocusmentioning

confidence: 55%

Temporal integration of visual signals in lens compensation (a review)

Zhu

2013

Experimental Eye Research

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“…Normal refractive development has been observed in light levels that have ranged upwards from 60 lux (Ehrlich et al, 1990) to 700 lux (Benavente-Perez et al, 2012; Li et al, 2000) but more typically have been in the 250 to 500 lux range (Ashby et al, 2010; Backhouse and Phillips, 2010; Callahan and Petry, 2000; Crewther and Crewther, 2002; Dong et al, 2011; Feldkaemper et al, 1999; Iuvone et al, 1978; Leech et al, 1995; McCarthy et al, 2007; Metlapally and McBrien, 2008; Smith et al, 2012; Vessey et al, 2005). The lights typically are on for 12 or 14 hours per day and off the remaining time.…”

Section: Animal Studiesmentioning

confidence: 99%

Light levels, refractive development, and myopia – A speculative review

Norton

Siegwart

2013

Experimental Eye Research

171

152

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Recent epidemiological evidence in children indicates that time spent outdoors is protective against myopia. Studies in animal models (chick, macaque, tree shrew) have found that light levels (similar to being in the shade outdoors) that are mildly elevated compared to indoor levels, slow form-deprivation myopia and (in chick and tree shrew) lens-induced myopia. Normal chicks raised in low light levels (50 lux) with a circadian light on/off cycle often develop spontaneous myopia. We propose a model in which the ambient illuminance levels produce a continuum of effects on normal refractive development and the response to myopiagenic stimuli such that low light levels favor myopia development and elevated levels are protective. Among possible mechanisms, elevation of retinal dopamine activity seems the most likely. Inputs from intrinsically-photosensitive retinal ganglion cells (ipRGCs) at elevated light levels may be involved, providing additional activation of retinal dopaminergic pathways.

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“…24,26,[31][32][33][34][35][36][37] Smith et al, 26 in particular, argued for a role of the peripheral retina in central refractive control when they showed that, in primates with and without functioning central retina, negative defocus lenses applied in a peripheral annulus still led to myopia development. Stone et al 31 established that different sizes of central or peripheral apertures in opaque goggles led to varying levels of myopia and increases in axial length in chickens.…”

Section: Discussionmentioning

confidence: 99%