Human Electroretinal Responses to Grating Patterns and Defocus Changes by Global Flash Multifocal Electroretinogram

Chin, Man Pan; Chu, Patrick H W; Cheong, Allen M. Y.; Chan, Ho Lung Henry

doi:10.1371/journal.pone.0123480

Cited by 24 publications

(47 citation statements)

References 76 publications

(100 reference statements)

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“…Previous studies of the effects of optical defocus on mfERG responses from human retina have shown that gmfERG response amplitudes tend to increase with imposed myopic defocus and decrease with hyperopic defocus, with the effects most pronounced in the mid-peripheral retina. [14][15][16] These previous findings appear to be at odds with the results of the present study in which areas of the retina experiencing more naturally occurring myopic defocus tended to exhibit lower response amplitudes than areas experiencing hyperopic defocus. There are several potential reasons for this apparent discrepancy.…”

Section: Discussioncontrasting

confidence: 99%

“…The DC component of the gmfERG represents a pooled response predominantly derived from photoreceptor and bipolar cell activity, whereas the IC component is thought to derive from cells within the inner retina (ganglion and amacrine cells) . Previous gmfERG experiments have reported a sign‐dependent response to imposed retinal defocus, with higher gmfERG amplitudes occurring with plus lens wear (focal plane located anterior to the retina, creating myopic retinal defocus) and reduced amplitudes with minus lens wear (creating hyperopic defocus) . However, although these experiments attempted to differentiate the response to imposed defocus at different retinal eccentricities, they did not directly quantify the sign or magnitude of defocus at these peripheral regions.…”

Section: Introductionmentioning

confidence: 99%

“…13 Previous gmfERG experiments have reported a sign-dependent response to imposed retinal defocus, with higher gmfERG amplitudes occurring with plus lens wear (focal plane located anterior to the retina, creating myopic retinal defocus) and reduced amplitudes with minus lens wear (creating hyperopic defocus). [14][15][16] However, although these experiments attempted to differentiate the response to imposed defocus at different retinal eccentricities, they did not directly quantify the sign or magnitude of defocus at these peripheral regions. Both the sign and magnitude of peripheral defocus (i.e.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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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“…19,20 Previous research in humans has shown that gmfERG responses are altered under conditions of retinal defocus, increasing with myopic defocus and decreasing with hyperopic defocus, with the effects most pronounced in the midperipheral retina. 21,22 The aim of this study was to investigate the effect of atropine on neural activity in the human retina under shortterm imposed defocus. We hypothesized that if the antimyopia effects of atropine are based on a retinal site of action, then atropine may modify the above gmfERG responses to retinal defocus.…”

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confidence: 99%

The Effect of Atropine on Human Global Flash mfERG Responses to Retinal Defocus

Khanal

Turnbull

Lee

et al. 2019

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. To investigate the action of atropine on global flash multifocal electroretinogram (gmfERG) responses to retinal defocus. METHOD. gmfERG recordings were made monocularly in 19 healthy adults under three lensimposed defocus conditions (2 diopters myopic, 2 diopters hyperopic, and no defocus) before and 24 hours after instillation of 1 drop of 0.1% atropine. Signals reflecting activity from the outer and inner retina (direct [DC] and induced [IC] components respectively) were analyzed. Responses were grouped into either a central (08-68) or peripheral (68-248) retinal zone. The gmfERG responses were compared relative to the no defocus, no atropine condition. RESULTS. Within the central zone, atropine had no effect on the amplitudes and peak times of DC or IC responses to defocus. For IC responses in the peripheral zone, there was a significant interaction effect of atropine and defocus (F 2,36 ¼ 6.050, P ¼ 0.011) with greater post-atropine amplitudes under myopic defocus (mean increase ¼ 15.5%, 95% confidence interval [CI] ¼ 5.6%-25.4%, P ¼ 0.004). Atropine also had a significant main effect of increasing IC peak times (F 1,18 ¼ 9.722, P ¼ 0.006). For DC responses, atropine had a significant main effect of increasing DC amplitudes (F 1,18 ¼ 7.821, P ¼ 0.012) and peak times (F 1,18 ¼ 15.406, P ¼ 0.001) regardless of sign of defocus. CONCLUSIONS. Our results imply that atropine acts in the inner layers of the peripheral retina to affect neuronal responses to myopic defocus, raising the possibility that atropine may potentiate the effects of myopic defocus in inhibiting eye growth.

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“…Recent data from Wolsley et al (2008), Ho et al (2012) and Chin et al (2015) confirms the dominant role of retina in the regulation of ocular growth. By using multifocal electroretinogram (mfERG) in humans, these authors have demonstrated dynamic changes in the peripheral retinal activity.…”

Section: The Autonomic Control Of Choroidal Thickness Changesmentioning

confidence: 82%

The Influence of the Autonomic Nervous System on the Human Choroid

Sander¹

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v AbstractThe impact of myopia is greater than just its optical consequences and in severe cases it can lead to a loss of vision. It is a highly prevalent eye disorder, with about one third of the population worldwide affected by this refractive error. Despite extensive research, the pathogenesis of myopia is still only partially understood. An improved knowledge of mechanisms underlying myopia is critical to developing new therapies to prevent myopia or to slow its progression.Although there is no fully effective and satisfactory myopia control treatment available, growing evidence has suggested that the choroid has a passive or active role in the regulation of eye growth and refractive error development. Numerous human and animal studies have shown that the retina can be moved forward or backward towards the image plane through changes in choroidal thickness, and these changes are likely to be associated in the longer term with eye growth and the development of refractive errors. As the choroid receives a rich innervation from the autonomic nervous system, many previous animal studies have utilized pharmacological agents and neurotoxins to elucidate the possible role of muscarinic signaling in the regulation of choroidal thickness, but only a few studies have investigated this issue in humans. An improved understanding of the mechanisms that control choroidal thickness may be important in developing new therapies for combating the development and progression of myopia.The research described in the thesis aimed to investigate the role of the autonomic nervous system in the control of choroidal thickness, axial length and the morphology In a series of experiments, we have confirmed that in humans under normal visual conditions, the parasympathetic nervous system is involved in the short-term regulation of subfoveal and parafoveal choroidal thickness, axial length and the morphology of the anterior sclera. The muscarinic blocker homatropine caused a significant subfoveal and parafoveal choroidal thickening, shortening of axial length, an enlargement of Schlemm's canal area and an increase in thickness of the conjunctival/episcleral complex. On the other hand, no notable changes in ocular parameters, except a decrease in the thickness of the conjunctival/episcleral tissues were found after instillation of the sympathomimetic drug phenylephrine.In an attempt to further improve our understanding of the myopigenic mechanisms influencing the thickness of the choroid in humans, we investigated the short-term influence of mixed interventions (positive and negative lens-imposed defocus / 2% homatropine) on choroidal thickness and axial length in emmetropic and myopic subjects. Homatropine prevented choroidal thinning in response to hyperopic defocus.This finding is consistent with the anti-myopia effects of muscarinic blockers and supports the potential importance of hyperopic defocus in the development of human myopia. By contrast, co-administration of homatropine with myopic defocus did not enhance the thicken...

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Human Electroretinal Responses to Grating Patterns and Defocus Changes by Global Flash Multifocal Electroretinogram

Cited by 24 publications

References 76 publications

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

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

The Effect of Atropine on Human Global Flash mfERG Responses to Retinal Defocus

The Influence of the Autonomic Nervous System on the Human Choroid

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