Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus

Anastasios John Kanellopoulos,1,2 George Asimellis11Laservision.gr Eye Institute, Athens, Greece; 2New York University School of Medicine, Department of Opthalmology, NY, NY, USABackground: The purpose of this study was to compare the safety and efficacy of two alternative corneal topograph...

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Autores principales:	Kanellopoulos AJ, Asimellis G
Formato:	article
Lenguaje:	EN
Publicado:	Dove Medical Press 2013
Materias:	Ophthalmology RE1-994
Acceso en línea:	https://doaj.org/article/43c6355b253549da9666f77b648d244b
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spelling	oai:doaj.org-article:43c6355b253549da9666f77b648d244b2021-12-02T01:55:34ZComparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus1177-54671177-5483https://doaj.org/article/43c6355b253549da9666f77b648d244b2013-07-01T00:00:00Zhttp://www.dovepress.com/comparison-of-placido-disc-and-scheimpflug-image-derived-topography-gu-a13693https://doaj.org/toc/1177-5467https://doaj.org/toc/1177-5483Anastasios John Kanellopoulos,1,2 George Asimellis11Laservision.gr Eye Institute, Athens, Greece; 2New York University School of Medicine, Department of Opthalmology, NY, NY, USABackground: The purpose of this study was to compare the safety and efficacy of two alternative corneal topography data sources used in topography-guided excimer laser normalization, combined with corneal collagen cross-linking in the management of keratoconus using the Athens protocol, ie, a Placido disc imaging device and a Scheimpflug imaging device.Methods: A total of 181 consecutive patients with keratoconus who underwent the Athens protocol between 2008 and 2011 were studied preoperatively and at months 1, 3, 6, and 12 postoperatively for visual acuity, keratometry, and anterior surface corneal irregularity indices. Two groups were formed, depending on the primary source used for topoguided photoablation, ie, group A (Placido disc) and group B (Scheimpflug rotating camera). One-year changes in visual acuity, keratometry, and seven anterior surface corneal irregularity indices were studied in each group.Results: Changes in visual acuity, expressed as the difference between postoperative and preoperative corrected distance visual acuity were +0.12 ± 0.20 (range +0.60 to -0.45) for group A and +0.19 ± 0.20 (range +0.75 to -0.30) for group B. In group A, K1 (flat keratometry) changed from 45.202 ± 3.782 D to 43.022 ± 3.819 D, indicating a flattening of -2.18 D, and K2 (steep keratometry) changed from 48.670 ± 4.066 D to 45.865 ± 4.794 D, indicating a flattening of -2.805 D. In group B, K1 (flat keratometry) changed from 46.213 ± 4.082 D to 43.190 ± 4.398 D, indicating a flattening of -3.023 D, and K2 (steep keratometry) changed from 50.774 ± 5.210 D to 46.380 ± 5.006 D, indicating a flattening of -4.394 D. For group A, the index of surface variance decreased to -5.07% and the index of height decentration to -26.81%. In group B, the index of surface variance decreased to -18.35% and the index of height decentration to -39.03%. These reductions indicate that the corneal surface became less irregular (index of surface variance) and the “cone” flatter and more central (index of height decentration) postoperatively.Conclusion: Of the two sources of primary corneal data, the Scheimpflug rotating camera (Oculyzer™) for topography-guided normalization treatment with the WaveLight excimer laser platform appeared to provide more statistically significant improvement than the Placido disc topographer (Topolyzer™). Overall, the Athens protocol, aiming both to halt progression of keratoconic ectasia and to improve corneal topometry and visual performance, produced safe and satisfactory refractive, keratometric, and topometric results. The observed changes in visual acuity, along with keratometric flattening and topometric improvement, are suggestive of overall postoperative improvement.Keywords: Athens protocol, anterior Pentacam indices, keratoconus, cross-linking, WaveLight/Alcon excimer laser, EX500 excimer laser, higher fluence collagen cross-linkingKanellopoulos AJAsimellis GDove Medical PressarticleOphthalmologyRE1-994ENClinical Ophthalmology, Vol 2013, Iss default, Pp 1385-1396 (2013)
institution	DOAJ
collection	DOAJ
language	EN
topic	Ophthalmology RE1-994
spellingShingle	Ophthalmology RE1-994 Kanellopoulos AJ Asimellis G Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus
description	Anastasios John Kanellopoulos,1,2 George Asimellis11Laservision.gr Eye Institute, Athens, Greece; 2New York University School of Medicine, Department of Opthalmology, NY, NY, USABackground: The purpose of this study was to compare the safety and efficacy of two alternative corneal topography data sources used in topography-guided excimer laser normalization, combined with corneal collagen cross-linking in the management of keratoconus using the Athens protocol, ie, a Placido disc imaging device and a Scheimpflug imaging device.Methods: A total of 181 consecutive patients with keratoconus who underwent the Athens protocol between 2008 and 2011 were studied preoperatively and at months 1, 3, 6, and 12 postoperatively for visual acuity, keratometry, and anterior surface corneal irregularity indices. Two groups were formed, depending on the primary source used for topoguided photoablation, ie, group A (Placido disc) and group B (Scheimpflug rotating camera). One-year changes in visual acuity, keratometry, and seven anterior surface corneal irregularity indices were studied in each group.Results: Changes in visual acuity, expressed as the difference between postoperative and preoperative corrected distance visual acuity were +0.12 ± 0.20 (range +0.60 to -0.45) for group A and +0.19 ± 0.20 (range +0.75 to -0.30) for group B. In group A, K1 (flat keratometry) changed from 45.202 ± 3.782 D to 43.022 ± 3.819 D, indicating a flattening of -2.18 D, and K2 (steep keratometry) changed from 48.670 ± 4.066 D to 45.865 ± 4.794 D, indicating a flattening of -2.805 D. In group B, K1 (flat keratometry) changed from 46.213 ± 4.082 D to 43.190 ± 4.398 D, indicating a flattening of -3.023 D, and K2 (steep keratometry) changed from 50.774 ± 5.210 D to 46.380 ± 5.006 D, indicating a flattening of -4.394 D. For group A, the index of surface variance decreased to -5.07% and the index of height decentration to -26.81%. In group B, the index of surface variance decreased to -18.35% and the index of height decentration to -39.03%. These reductions indicate that the corneal surface became less irregular (index of surface variance) and the “cone” flatter and more central (index of height decentration) postoperatively.Conclusion: Of the two sources of primary corneal data, the Scheimpflug rotating camera (Oculyzer™) for topography-guided normalization treatment with the WaveLight excimer laser platform appeared to provide more statistically significant improvement than the Placido disc topographer (Topolyzer™). Overall, the Athens protocol, aiming both to halt progression of keratoconic ectasia and to improve corneal topometry and visual performance, produced safe and satisfactory refractive, keratometric, and topometric results. The observed changes in visual acuity, along with keratometric flattening and topometric improvement, are suggestive of overall postoperative improvement.Keywords: Athens protocol, anterior Pentacam indices, keratoconus, cross-linking, WaveLight/Alcon excimer laser, EX500 excimer laser, higher fluence collagen cross-linking
format	article
author	Kanellopoulos AJ Asimellis G
author_facet	Kanellopoulos AJ Asimellis G
author_sort	Kanellopoulos AJ
title	Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus
title_short	Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus
title_full	Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus
title_fullStr	Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus
title_full_unstemmed	Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus
title_sort	comparison of placido disc and scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence cxl: the athens protocol, in progressive keratoconus
publisher	Dove Medical Press
publishDate	2013
url	https://doaj.org/article/43c6355b253549da9666f77b648d244b
work_keys_str_mv	AT kanellopoulosaj comparisonofplacidodiscandscheimpflugimagederivedtopographyguidedexcimerlasersurfacenormalizationcombinedwithhigherfluencecxltheathensprotocolinprogressivekeratoconus AT asimellisg comparisonofplacidodiscandscheimpflugimagederivedtopographyguidedexcimerlasersurfacenormalizationcombinedwithhigherfluencecxltheathensprotocolinprogressivekeratoconus
_version_	1718402771186614272

Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus

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