IMI – Report on Experimental Models of Emmetropization and Myopia

Troilo, David; Smith, Earl L.; Nickla, Debora L.; Ashby, Regan; Tkatchenko, Andrei V.; Ostrin, Lisa A; Gawne, Timothy J.; Pardue, Machelle T.; Summers, Jody A.; Kee, Chea Su; Schroedl, Falk; Wahl, Siegfried; Jones, Lyndon

doi:10.1167/iovs.18-25967

Cited by 311 publications

(320 citation statements)

References 728 publications

(1,321 reference statements)

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“…Studies also use lenses to alter the image plane with respect to the retina, resulting in image defocus that induces compensatory alterations in ocular growth, known as lens‐induced myopia or hyperopia . Both form‐deprivation and lens‐induced defocus result in abnormal eye growth and refractive error development, with associated anatomical, optical, and biochemical changes in the anterior and posterior segments of the eye (see inclusive reviews) . In this section, we will define the process of emmetropisation, summarise different optical aspects of FDM and lens‐induced ametropias, including their similarities and differences, and describe how these experimental models have informed us about refractive error development in humans.…”

Section: Optical Defocus and Visual Regulation Of Ocular Growthmentioning

confidence: 99%

“…As shown in Figure , a large part of our current knowledge of visual regulation of ocular growth has originated from experimental studies describing the ability of the eye to compensate for myopic or hyperopic defocus, imposed with positive or negative lenses, respectively. When defocus is induced, the eye undergoes compensatory changes in ocular growth to match its axial length to the altered focal plane, thereby decreasing or eliminating the imposed refractive error . Myopic defocus induced with positive lenses leads to a thickening of the choroid which brings the retina forward, a slowing of axial elongation, and a hyperopic shift in refraction.…”

Section: Optical Defocus and Visual Regulation Of Ocular Growthmentioning

confidence: 99%

“…During lens‐imposed defocus, the sign, frequency, duration, and magnitude of defocus experienced by the eye change constantly depending on the visual scene. Therefore, the nature of vision‐dependent eye growth depends on the temporal integration of visual signals over time (see reviews) . Previous studies have shown that the temporal integration of visual signals for ocular growth regulation is non‐linear.…”

Section: Optical Defocus and Visual Regulation Of Ocular Growthmentioning

confidence: 99%

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Optical mechanisms regulating emmetropisation and refractive errors: evidence from animal models

Chakraborty

Ostrin

Benavente-Perez

et al. 2020

Clinical and Experimental Optometry

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Our current understanding of emmetropisation and myopia development has evolved from decades of work in various animal models, including chicks, non‐human primates, tree shrews, guinea pigs, and mice. Extensive research on optical, biochemical, and environmental mechanisms contributing to refractive error development in animal models has provided insights into eye growth in humans. Importantly, animal models have taught us that eye growth is locally controlled within the eye, and can be influenced by the visual environment. This review will focus on information gained from animal studies regarding the role of optical mechanisms in guiding eye growth, and how these investigations have inspired studies in humans. We will first discuss how researchers came to understand that emmetropisation is guided by visual feedback, and how this can be manipulated by form‐deprivation and lens‐induced defocus to induce refractive errors in animal models. We will then discuss various aspects of accommodation that have been implicated in refractive error development, including accommodative microfluctuations and accommodative lag. Next, the impact of higher order aberrations and peripheral defocus will be discussed. Lastly, recent evidence suggesting that the spectral and temporal properties of light influence eye growth, and how this might be leveraged to treat myopia in children, will be presented. Taken together, these findings from animal models have significantly advanced our knowledge about the optical mechanisms contributing to eye growth in humans, and will continue to contribute to the development of novel and effective treatment options for slowing myopia progression in children.

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Section: Optical Defocus and Visual Regulation Of Ocular Growthmentioning

confidence: 99%

Section: Optical Defocus and Visual Regulation Of Ocular Growthmentioning

confidence: 99%

Section: Optical Defocus and Visual Regulation Of Ocular Growthmentioning

confidence: 99%

See 1 more Smart Citation

Optical mechanisms regulating emmetropisation and refractive errors: evidence from animal models

Chakraborty

Ostrin

Benavente-Perez

et al. 2020

Clinical and Experimental Optometry

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“…It has been suggested that the dominant role of the peripheral retina in this regard is likely due to spatial summation and the greater absolute number of neurons in the peripheral versus central retina . Although the way in which local sign of defocus is computed from the retinal image is not understood, it is generally held that it is the sign of the spherical component of defocus which determines the eye growth signal, with myopic defocus slowing eye growth and hyperopic defocus accelerating it …”

Section: Introductionmentioning

confidence: 99%

Global‐flash mfERG responses to local differences in spherical and astigmatic defocus across the human retina

Turnbull

Goodman

Phillips

2019

Ophthalmic Physiologic Optic

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Purpose Emmetropisation is essentially a visually guided, within‐eye process. We investigated differences in global‐flash multifocal electroretinogram (gmfERG) responses to naturally occurring differences in spherical and astigmatic defocus across the retina, which might provide a basis for guiding eye growth. Methods Experiment 1: The gmfERG responses (direct, DC, and induced, IC, amplitudes and latencies) recorded simultaneously from six retinal areas (15° eccentricity, spaced at 60°, areas 3.2°2) were correlated with the uncorrected retinal defocus measured at the six corresponding retinal locations in 20 adults with foveal refractive errors (−4.75 to +1.25D). No correcting lenses were used to avoid introduction of lens‐induced aberrations and magnification. Experiment 2 investigated the effect of superimposing astigmatic defocus (+2.00/−4.00D Jackson Cross Cylinder presented at four orientations) on gmfERG responses. Results Experiment 1: DC and IC response amplitudes were greater in retinal regions naturally exposed to more hyperopic spherical defocus (DC: rho = 0.26, p = 0.005; IC: rho = 0.29, p = 0.001), but response latencies were unaffected by sign or magnitude of spherical defocus (DC: p = 0.34; IC: p = 0.40). Response amplitudes and latencies were unaffected by astigmatic defocus. Experiment 2: Rotating the JCC axis to four different orientations had no effect on the gmfERG responses (DC amplitude, p = 0.39; DC latency, p = 0.10; IC amplitude, p = 0.51; IC latency, p = 0.64). Conclusion The gmfERG responses from discrete retinal areas varied with the sign and magnitude of local spherical defocus, but we found no evidence that retinal responses were affected by astigmatic defocus. Therefore, local astigmatism is unlikely to provide cues for controlling eye growth, whereas differences in response to spherical defocus between different retinal regions could potentially provide cues for controlling eye growth in emmetropisation.

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“…The rationale for prescribing under‐correction for myopia is to bring the image shell in front of the retina to present a retarding blur stimulus based on findings from animal studies . It is also considered to be an attempt to reduce the accommodative stimulus and demand at near and thus reduce the blur that drives accommodation .…”

mentioning

confidence: 99%

Role of un‐correction, under‐correction and over‐correction of myopia as a strategy for slowing myopic progression

Logan

Wolffsohn

2020

Clinical and Experimental Optometry

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This systematic review investigates the association between un‐, under‐ and over‐correction of myopic refractive error and myopia progression in children and adolescents (up to 18 years of age). The literature search included three databases (PubMed, Web of Science, and Cochrane Central Register of Controlled Trials [CENTRAL]), and reference lists of retrieved studies in any language. Eight prospective cohort studies and one retrospective analysis of clinical data provided comparison data on un‐ and under‐correction of myopia versus full‐correction of myopia; however, the quality of studies and length of follow‐up times varied. A forest plot showed no beneficial effect of under‐correction with some studies finding an increase in myopia progression. While one study suggested that myopia progression is slower in an un‐corrected cohort compared to those who are fully corrected, another study suggests the opposite. One study utilised anisomyopes to allow comparison of under‐correction of one eye with full‐correction of the fellow eye indicating that under‐correction in one eye appears to slow the rate of myopia progression in that eye. Another study on full‐correction only in one eye found that progression was faster in the un‐corrected eye. No benefits of over‐correction of myopia was found. The overall findings are equivocal with under‐correction causing a faster rate of myopia progression. There is no strong evidence of benefits from un‐correction, monovision or over‐correction. Hence, current clinical advice advocates for the full‐correction of myopia. Further studies are warranted to determine the level of myopia that can be left uncorrected without impacting on myopia progression and how this changes with time.

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IMI – Report on Experimental Models of Emmetropization and Myopia

Cited by 311 publications

References 728 publications

Optical mechanisms regulating emmetropisation and refractive errors: evidence from animal models

Optical mechanisms regulating emmetropisation and refractive errors: evidence from animal models

Global‐flash mfERG responses to local differences in spherical and astigmatic defocus across the human retina

Role of un‐correction, under‐correction and over‐correction of myopia as a strategy for slowing myopic progression

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