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Influence of different types of astigmatism on visual acuity
PURPOSE: To investigate the change in visual acuity (VA) produced by different types of astigmatism (on the basis of the refractive power and position of the principal meridians) on normal accommodating eyes. METHODS: The lens induced method was employed to simulate a set of 28 astigmatic blur condi...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Elsevier
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5484781/ https://www.ncbi.nlm.nih.gov/pubmed/27639497 http://dx.doi.org/10.1016/j.optom.2016.07.003 |
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author | Remón, Laura Monsoriu, Juan A. Furlan, Walter D. |
author_facet | Remón, Laura Monsoriu, Juan A. Furlan, Walter D. |
author_sort | Remón, Laura |
collection | PubMed |
description | PURPOSE: To investigate the change in visual acuity (VA) produced by different types of astigmatism (on the basis of the refractive power and position of the principal meridians) on normal accommodating eyes. METHODS: The lens induced method was employed to simulate a set of 28 astigmatic blur conditions on different healthy emmetropic eyes. Additionally, 24 values of spherical defocus were also simulated on the same eyes for comparison. VA was measured in each case and the results, expressed in logMAR units, were represented against of the modulus of the dioptric power vector (blur strength). RESULTS: LogMAR VA varies in a linear fashion with increasing astigmatic blur, being the slope of the line dependent on the accommodative demand in each type of astigmatism. However, in each case, we found no statistically significant differences between the three axes investigated (0°, 45°, 90°). Non-statistically significant differences were found either for the VA achieved with spherical myopic defocus (MD) and mixed astigmatism (MA). VA with simple hyperopic astigmatism (SHA) was higher than with simple myopic astigmatism (SMA), however, in this case non conclusive results were obtained in terms of statistical significance. The VA achieved with imposed compound hyperopic astigmatism (CHA) was highly influenced by the eye's accommodative response. CONCLUSIONS: VA is correlated with the blur strength in a different way for each type of astigmatism, depending on the accommodative demand. VA is better when one of the focal lines lie on the retina irrespective of the axis orientation; accommodation favors this situation. |
format | Online Article Text |
id | pubmed-5484781 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Elsevier |
record_format | MEDLINE/PubMed |
spelling | pubmed-54847812017-07-10 Influence of different types of astigmatism on visual acuity Remón, Laura Monsoriu, Juan A. Furlan, Walter D. J Optom Original Article PURPOSE: To investigate the change in visual acuity (VA) produced by different types of astigmatism (on the basis of the refractive power and position of the principal meridians) on normal accommodating eyes. METHODS: The lens induced method was employed to simulate a set of 28 astigmatic blur conditions on different healthy emmetropic eyes. Additionally, 24 values of spherical defocus were also simulated on the same eyes for comparison. VA was measured in each case and the results, expressed in logMAR units, were represented against of the modulus of the dioptric power vector (blur strength). RESULTS: LogMAR VA varies in a linear fashion with increasing astigmatic blur, being the slope of the line dependent on the accommodative demand in each type of astigmatism. However, in each case, we found no statistically significant differences between the three axes investigated (0°, 45°, 90°). Non-statistically significant differences were found either for the VA achieved with spherical myopic defocus (MD) and mixed astigmatism (MA). VA with simple hyperopic astigmatism (SHA) was higher than with simple myopic astigmatism (SMA), however, in this case non conclusive results were obtained in terms of statistical significance. The VA achieved with imposed compound hyperopic astigmatism (CHA) was highly influenced by the eye's accommodative response. CONCLUSIONS: VA is correlated with the blur strength in a different way for each type of astigmatism, depending on the accommodative demand. VA is better when one of the focal lines lie on the retina irrespective of the axis orientation; accommodation favors this situation. Elsevier 2017 2016-09-14 /pmc/articles/PMC5484781/ /pubmed/27639497 http://dx.doi.org/10.1016/j.optom.2016.07.003 Text en © 2016 Spanish General Council of Optometry. Published by Elsevier Espa˜na, S.L.U. http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). |
spellingShingle | Original Article Remón, Laura Monsoriu, Juan A. Furlan, Walter D. Influence of different types of astigmatism on visual acuity |
title | Influence of different types of astigmatism on visual acuity |
title_full | Influence of different types of astigmatism on visual acuity |
title_fullStr | Influence of different types of astigmatism on visual acuity |
title_full_unstemmed | Influence of different types of astigmatism on visual acuity |
title_short | Influence of different types of astigmatism on visual acuity |
title_sort | influence of different types of astigmatism on visual acuity |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5484781/ https://www.ncbi.nlm.nih.gov/pubmed/27639497 http://dx.doi.org/10.1016/j.optom.2016.07.003 |
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