The influence of downward gaze and accommodation on ocular aberrations over time

Ghosh, Atanu; Collins, Michael J.; Read, Scott A.; Davis, Brett A.; Iskander, D. Robert

doi:10.1167/11.10.17

Cited by 20 publications

(21 citation statements)

References 43 publications

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“…Moreover, the differences in instruments used (COAS vs. Zywave) and the pupil diameter analyzed (5 vs. 6 mm) are other possible explanations for the discrepancy between studies. As suggested by previous published data, 53,54 the trend for the Y trefoil to shift in the negative direction and vertical coma to shift in the positive direction might be associated with the eyelid pressure acting on the corneal surface; however, because we did not measure the mechanical properties and morphology of the eyelid, this biomechanical factor needs further investigation.…”

Section: Discussionmentioning

confidence: 79%

Ocular Aberrations and Corneal Shape in Adults with and without Astigmatism

Leung

Lam

Kee

2015

Optometry and Vision Science

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Section: Discussionmentioning

confidence: 79%

Ocular Aberrations and Corneal Shape in Adults with and without Astigmatism

Leung

Lam

Kee

2015

Optometry and Vision Science

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“…For a fixed pupil diameter, HOA RMS consistently increases with greater accommodation demands, although some have found this occurs only with demands above 3 D . The major consistent change in HOAs that occurs during accommodation is a decrease in primary spherical aberration (

Z_{4}^{0}

), becoming less positive or more negative . Secondary spherical aberration (

Z_{6}^{0}

) also undergoes a relatively small change, but is less consistent with respect to the direction of change.…”

Section: Hoas During Near Work and Accommodationmentioning

confidence: 96%

“…The on‐axis HOA profile also varies during downgaze, with most of the change arising from a negative shift in primary trefoil (

Z_{3}^{- 3}

) and positive shifts in secondary spherical aberration (

Z_{6}^{0}

) and primary (

Z_{3}^{- 1}

) and secondary vertical coma (

Z_{5}^{- 1}

), although significant changes also occur in secondary astigmatism (

Z_{4}^{- 2}

and

Z_{4}^{2}

), tetrafoil (

Z_{4}^{4}

) and pentafoil (

Z_{5}^{- 5}

) . Ghosh et al also showed that accommodation during downgaze produced a greater negative shift in primary spherical aberration (

Z_{4}^{0}

) and primary vertical coma (

Z_{3}^{- 1}

), and a greater positive shift in secondary spherical aberration (

Z_{6}^{0}

) than during accommodation alone.…”

Section: Hoas During Near Work and Accommodationmentioning

confidence: 99%

“…The on‐axis HOA profile also varies during downgaze, with most of the change arising from a negative shift in primary trefoil (

Z_{3}^{- 3}

) and positive shifts in secondary spherical aberration (

Z_{6}^{0}

) and primary (

Z_{3}^{- 1}

) and secondary vertical coma (

Z_{5}^{- 1}

), although significant changes also occur in secondary astigmatism (

Z_{4}^{- 2}

and

Z_{4}^{2}

), tetrafoil (

Z_{4}^{4}

) and pentafoil (

Z_{5}^{- 5}

) . Ghosh et al also showed that accommodation during downgaze produced a greater negative shift in primary spherical aberration (

Z_{4}^{0}

) and primary vertical coma (

Z_{3}^{- 1}

), and a greater positive shift in secondary spherical aberration (

Z_{6}^{0}

) than during accommodation alone. Given these findings, and that anterior corneal HOAs and elevation remain stable during accommodation in primary gaze, the changes in terms such as primary vertical coma (

Z_{3}^{- 1}

) and trefoil (

Z_{3}^{- 3}

) during downgaze (and near work) are likely associated with lid‐induced corneal deformation at the superior pupil margin, while the variations in primary (

Z_{4}^{0}

) and secondary (

Z_{6}^{0}

) spherical aberration are likely the result of accommodation.…”

Section: Hoas During Near Work and Accommodationmentioning

confidence: 99%

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Higher order aberrations, refractive error development and myopia control: a review

Hughes

Vincent

Read

et al. 2020

Clinical and Experimental Optometry

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Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result in predictable changes in axial eye growth. Higher order aberrations are optical imperfections of the eye that alter retinal image quality despite optimal correction of spherical defocus and astigmatism. Since higher order aberrations reduce retinal image quality and produce variations in optical vergence across the entrance pupil of the eye, they may provide optical signals that contribute to the regulation and modulation of eye growth and refractive error development. The magnitude and type of higher order aberrations vary with age, refractive error, and during near work and accommodation. Furthermore, distinctive changes in higher order aberrations occur with various myopia control treatments, including atropine, near addition spectacle lenses, orthokeratology and soft multifocal and dual‐focus contact lenses. Several plausible mechanisms have been proposed by which higher order aberrations may influence axial eye growth, the development of refractive error, and the treatment effect of myopia control interventions. Future studies of higher order aberrations, particularly during childhood, accommodation, and treatment with myopia control interventions are required to further our understanding of their potential role in refractive error development and eye growth.

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“…Tonic accommodation measurements were obtained with a modified commercial Shack-Hartmann wavefront sensor. The modification included the addition of a relay lens system and a beam splitter to allow on-axis aberration measurement in primary gaze (Ghosh et al, 2011b) to enable open-field objective refraction measurements, as well as a Maxwellian view system in order to open the accommodation feedback loop under the ambient room illumination.…”

Section: Methodsmentioning

confidence: 99%

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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The influence of downward gaze and accommodation on ocular aberrations over time

Cited by 20 publications

References 43 publications

Ocular Aberrations and Corneal Shape in Adults with and without Astigmatism

Ocular Aberrations and Corneal Shape in Adults with and without Astigmatism

Higher order aberrations, refractive error development and myopia control: a review

The Influence of the Autonomic Nervous System on the Human Choroid

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