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The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur

PURPOSE: To investigate the change in axial length (AxL) and choroidal thickness (ChT) in response to continuous and alternating episodes of monocular myopic and hyperopic defocus. METHODS: The right eye of sixteen young adults was exposed to 60 minute episodes of either continuous or alternating my...

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Detalles Bibliográficos
Autores principales: Delshad, Samaneh, Collins, Michael John, Read, Scott Andrew, Vincent, Stephen James
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710071/
https://www.ncbi.nlm.nih.gov/pubmed/33264356
http://dx.doi.org/10.1371/journal.pone.0243076
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author Delshad, Samaneh
Collins, Michael John
Read, Scott Andrew
Vincent, Stephen James
author_facet Delshad, Samaneh
Collins, Michael John
Read, Scott Andrew
Vincent, Stephen James
author_sort Delshad, Samaneh
collection PubMed
description PURPOSE: To investigate the change in axial length (AxL) and choroidal thickness (ChT) in response to continuous and alternating episodes of monocular myopic and hyperopic defocus. METHODS: The right eye of sixteen young adults was exposed to 60 minute episodes of either continuous or alternating myopic and hyperopic defocus (+3 DS & -3 DS) over six separate days, with the left eye optimally corrected for distance. During alternating defocus conditions, the eye was exposed to either 30 or 15 minute cycles of myopic and hyperopic defocus, with the order of defocus reversed in separate sessions. The AxL and ChT of the right eye were measured before, during and after each defocus condition. RESULTS: Significant changes in AxL were observed over time, dependent upon the defocus condition (p < 0.0001). In general, AxL exhibited a greater magnitude of change during continuous than alternating defocus conditions. The maximum AxL elongation was +7 ± 7 μm (p = 0.010) in response to continuous hyperopic defocus and the maximum AxL reduction was -8 ± 10 μm of (p = 0.046) in response to continuous myopic defocus. During both 30 and 15 minute cycles of alternating myopic and hyperopic defocus of equal duration, the effect of opposing blur sessions cancelled each other and the AxL was near baseline levels following the final defocus session (mean change from baseline across all alternating defocus conditions was +2 ± 10 μm, p > 0.05). Similar, but smaller magnitude, changes were observed for ChT. CONCLUSIONS: The human eye appears capable of temporal averaging of visual cues from alternating myopic and hyperopic defocus. In the short term, this integration appears to be a cancellation of the effects of the preceding defocus condition of opposite sign.
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spelling pubmed-77100712020-12-03 The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur Delshad, Samaneh Collins, Michael John Read, Scott Andrew Vincent, Stephen James PLoS One Research Article PURPOSE: To investigate the change in axial length (AxL) and choroidal thickness (ChT) in response to continuous and alternating episodes of monocular myopic and hyperopic defocus. METHODS: The right eye of sixteen young adults was exposed to 60 minute episodes of either continuous or alternating myopic and hyperopic defocus (+3 DS & -3 DS) over six separate days, with the left eye optimally corrected for distance. During alternating defocus conditions, the eye was exposed to either 30 or 15 minute cycles of myopic and hyperopic defocus, with the order of defocus reversed in separate sessions. The AxL and ChT of the right eye were measured before, during and after each defocus condition. RESULTS: Significant changes in AxL were observed over time, dependent upon the defocus condition (p < 0.0001). In general, AxL exhibited a greater magnitude of change during continuous than alternating defocus conditions. The maximum AxL elongation was +7 ± 7 μm (p = 0.010) in response to continuous hyperopic defocus and the maximum AxL reduction was -8 ± 10 μm of (p = 0.046) in response to continuous myopic defocus. During both 30 and 15 minute cycles of alternating myopic and hyperopic defocus of equal duration, the effect of opposing blur sessions cancelled each other and the AxL was near baseline levels following the final defocus session (mean change from baseline across all alternating defocus conditions was +2 ± 10 μm, p > 0.05). Similar, but smaller magnitude, changes were observed for ChT. CONCLUSIONS: The human eye appears capable of temporal averaging of visual cues from alternating myopic and hyperopic defocus. In the short term, this integration appears to be a cancellation of the effects of the preceding defocus condition of opposite sign. Public Library of Science 2020-12-02 /pmc/articles/PMC7710071/ /pubmed/33264356 http://dx.doi.org/10.1371/journal.pone.0243076 Text en © 2020 Delshad et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Delshad, Samaneh
Collins, Michael John
Read, Scott Andrew
Vincent, Stephen James
The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur
title The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur
title_full The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur
title_fullStr The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur
title_full_unstemmed The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur
title_short The human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur
title_sort human axial length and choroidal thickness responses to continuous and alternating episodes of myopic and hyperopic blur
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710071/
https://www.ncbi.nlm.nih.gov/pubmed/33264356
http://dx.doi.org/10.1371/journal.pone.0243076
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