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...
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| Format: | Article |
| Language: | English |
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Elsevier
2017-07-01
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| Series: | Journal of Optometry |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1888429616300498 |
| _version_ | 1819052494367490048 |
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| author | Laura Remón Juan A. Monsoriu Walter D. Furlan |
| author_facet | Laura Remón Juan A. Monsoriu Walter D. Furlan |
| author_sort | Laura Remón |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-12-21T12:20:44Z |
| format | Article |
| id | doaj.art-b157ffbeec2f41fd889249529ae9a95b |
| institution | Directory Open Access Journal |
| issn | 1888-4296 |
| language | English |
| last_indexed | 2024-12-21T12:20:44Z |
| publishDate | 2017-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Optometry |
| spelling | doaj.art-b157ffbeec2f41fd889249529ae9a95b2022-12-21T19:04:19ZengElsevierJournal of Optometry1888-42962017-07-0110314114810.1016/j.optom.2016.07.003Influence of different types of astigmatism on visual acuityLaura Remón0Juan A. Monsoriu1Walter D. Furlan2Centro de Tecnologías Físicas, Universitat Politècnica de València, 46022 Valencia, SpainCentro de Tecnologías Físicas, Universitat Politècnica de València, 46022 Valencia, SpainDepartamento de Óptica y Optometría y Ciencias de la Visión, Universitat de València, 46100 Burjassot, SpainPurpose: 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.http://www.sciencedirect.com/science/article/pii/S1888429616300498Visual acuityAstigmatismSpherical defocusAccommodation stateAxis |
| spellingShingle | Laura Remón Juan A. Monsoriu Walter D. Furlan Influence of different types of astigmatism on visual acuity Journal of Optometry Visual acuity Astigmatism Spherical defocus Accommodation state Axis |
| 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 | Visual acuity Astigmatism Spherical defocus Accommodation state Axis |
| url | http://www.sciencedirect.com/science/article/pii/S1888429616300498 |
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