Biomechanical corneal changes induced by different flap thickness created by femtosecond laser
Autor(a) principal: | |
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Data de Publicação: | 2011 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Clinics |
Texto Completo: | https://www.revistas.usp.br/clinics/article/view/19529 |
Resumo: | OBJECTIVE: To evaluate the impact of the creation of corneal flaps at different thicknesses on the biomechanical properties of swine corneas. METHOD: Twelve swine eyes were obtained to form two groups: 100 μm flap thickness and 300 μm flap thickness. Each eye was submitted to the following examinations: raster topography to investigate corneal curvature alterations, ocular response analyzer to investigate corneal hysteresis change, optical coherence tomography to measure central corneal and flap thickness and sonic wave propagation velocity as a measure of stiffness, before and immediately after flap creation. After flap amputation, surface wave velocity measurements were repeated. RESULTS: Measured flap thicknesses were statistically different for thin and thick flap groups, with an average of 108.5 + 6.9 and 307.8 + 11.5 μm respectively. Hysteresis and corneal resistance factor did not change significantly after flap creation in the thin flap group. With thicker flaps, both parameters decreased significantly from 8.0 +1.0 to 5.1 +1.5 mmHg and from 8.2 + 1.6 to 4.1 +2.5 mmHg respectively. Simulated keratometry values increased in the thick flap group (from 39.5 + 1 D to 45.9+1.2 D) after flap creation but not in the thin flap group (from 40.6 + 0.6 D to 41.4+ 1.0 D). Regarding surface wave velocity analysis, the surgical procedures induced statistically lower results in some positions. CONCLUSION: In the experimental conditions established by this model, thicker flaps presented a greater biomechanical impact on the cornea. |
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Clinics |
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Biomechanical corneal changes induced by different flap thickness created by femtosecond laser LASIKFlapsEctasiaFemtosecond laserCornea OBJECTIVE: To evaluate the impact of the creation of corneal flaps at different thicknesses on the biomechanical properties of swine corneas. METHOD: Twelve swine eyes were obtained to form two groups: 100 μm flap thickness and 300 μm flap thickness. Each eye was submitted to the following examinations: raster topography to investigate corneal curvature alterations, ocular response analyzer to investigate corneal hysteresis change, optical coherence tomography to measure central corneal and flap thickness and sonic wave propagation velocity as a measure of stiffness, before and immediately after flap creation. After flap amputation, surface wave velocity measurements were repeated. RESULTS: Measured flap thicknesses were statistically different for thin and thick flap groups, with an average of 108.5 + 6.9 and 307.8 + 11.5 μm respectively. Hysteresis and corneal resistance factor did not change significantly after flap creation in the thin flap group. With thicker flaps, both parameters decreased significantly from 8.0 +1.0 to 5.1 +1.5 mmHg and from 8.2 + 1.6 to 4.1 +2.5 mmHg respectively. Simulated keratometry values increased in the thick flap group (from 39.5 + 1 D to 45.9+1.2 D) after flap creation but not in the thin flap group (from 40.6 + 0.6 D to 41.4+ 1.0 D). Regarding surface wave velocity analysis, the surgical procedures induced statistically lower results in some positions. CONCLUSION: In the experimental conditions established by this model, thicker flaps presented a greater biomechanical impact on the cornea. Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo2011-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://www.revistas.usp.br/clinics/article/view/1952910.1590/S1807-59322011000600025Clinics; Vol. 66 No. 6 (2011); 1067-1071 Clinics; v. 66 n. 6 (2011); 1067-1071 Clinics; Vol. 66 Núm. 6 (2011); 1067-1071 1980-53221807-5932reponame:Clinicsinstname:Universidade de São Paulo (USP)instacron:USPenghttps://www.revistas.usp.br/clinics/article/view/19529/21592Medeiros, Fabricio W.Sinha-Roy, AbhijitAlves, Milton R.Dupps Jr., William J.info:eu-repo/semantics/openAccess2012-05-23T16:47:02Zoai:revistas.usp.br:article/19529Revistahttps://www.revistas.usp.br/clinicsPUBhttps://www.revistas.usp.br/clinics/oai||clinics@hc.fm.usp.br1980-53221807-5932opendoar:2012-05-23T16:47:02Clinics - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser |
title |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser |
spellingShingle |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser Medeiros, Fabricio W. LASIK Flaps Ectasia Femtosecond laser Cornea |
title_short |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser |
title_full |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser |
title_fullStr |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser |
title_full_unstemmed |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser |
title_sort |
Biomechanical corneal changes induced by different flap thickness created by femtosecond laser |
author |
Medeiros, Fabricio W. |
author_facet |
Medeiros, Fabricio W. Sinha-Roy, Abhijit Alves, Milton R. Dupps Jr., William J. |
author_role |
author |
author2 |
Sinha-Roy, Abhijit Alves, Milton R. Dupps Jr., William J. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Medeiros, Fabricio W. Sinha-Roy, Abhijit Alves, Milton R. Dupps Jr., William J. |
dc.subject.por.fl_str_mv |
LASIK Flaps Ectasia Femtosecond laser Cornea |
topic |
LASIK Flaps Ectasia Femtosecond laser Cornea |
description |
OBJECTIVE: To evaluate the impact of the creation of corneal flaps at different thicknesses on the biomechanical properties of swine corneas. METHOD: Twelve swine eyes were obtained to form two groups: 100 μm flap thickness and 300 μm flap thickness. Each eye was submitted to the following examinations: raster topography to investigate corneal curvature alterations, ocular response analyzer to investigate corneal hysteresis change, optical coherence tomography to measure central corneal and flap thickness and sonic wave propagation velocity as a measure of stiffness, before and immediately after flap creation. After flap amputation, surface wave velocity measurements were repeated. RESULTS: Measured flap thicknesses were statistically different for thin and thick flap groups, with an average of 108.5 + 6.9 and 307.8 + 11.5 μm respectively. Hysteresis and corneal resistance factor did not change significantly after flap creation in the thin flap group. With thicker flaps, both parameters decreased significantly from 8.0 +1.0 to 5.1 +1.5 mmHg and from 8.2 + 1.6 to 4.1 +2.5 mmHg respectively. Simulated keratometry values increased in the thick flap group (from 39.5 + 1 D to 45.9+1.2 D) after flap creation but not in the thin flap group (from 40.6 + 0.6 D to 41.4+ 1.0 D). Regarding surface wave velocity analysis, the surgical procedures induced statistically lower results in some positions. CONCLUSION: In the experimental conditions established by this model, thicker flaps presented a greater biomechanical impact on the cornea. |
publishDate |
2011 |
dc.date.none.fl_str_mv |
2011-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.revistas.usp.br/clinics/article/view/19529 10.1590/S1807-59322011000600025 |
url |
https://www.revistas.usp.br/clinics/article/view/19529 |
identifier_str_mv |
10.1590/S1807-59322011000600025 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
https://www.revistas.usp.br/clinics/article/view/19529/21592 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo |
publisher.none.fl_str_mv |
Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo |
dc.source.none.fl_str_mv |
Clinics; Vol. 66 No. 6 (2011); 1067-1071 Clinics; v. 66 n. 6 (2011); 1067-1071 Clinics; Vol. 66 Núm. 6 (2011); 1067-1071 1980-5322 1807-5932 reponame:Clinics instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Clinics |
collection |
Clinics |
repository.name.fl_str_mv |
Clinics - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
||clinics@hc.fm.usp.br |
_version_ |
1800222757734055936 |