| Effect of air-flow on the evaluation of refractive surgery ablation patterns. | |
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MedLine Citation:
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PMID: 21369297 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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An Allegretto Eye-Q laser platform (Wavelight GmbH, Erlangen, Germany) was used to study the effect of air-flow speed on the ablation of artificial polymer corneas used for testing refractive surgery patterns. Flat samples of two materials (PMMA and Filofocon A) were ablated at four different air flow conditions. The shape and profile of the ablated surfaces were measured with a precise non-contact optical surface profilometer. Significant asymmetries in the measured profiles were found when the ablation was performed with the clinical air aspiration system, and also without air flow. Increasing air-flow produced deeper ablations, improved symmetry, and increased the repeatability of the ablation pattern. Shielding of the laser pulse by the plume of smoke during the ablation of plastic samples reduced the central ablation depth by more than 40% with no-air flow, 30% with clinical air aspiration, and 5% with 1.15 m/s air flow. A simple model based on non-inertial dragging of the particles by air flow predicts no central shielding with 2.3 m/s air flow, and accurately predicts (within 2 μm) the decrease of central ablation depth by shielding. The shielding effects for PMMA and Filofocon A were similar despite the differences in the ablation properties of the materials and the different full-shielding transmission coefficient, which is related to the number of particles ejected and their associated optical behavior. Air flow is a key factor in the evaluation of ablation patterns in refractive surgery using plastic models, as significant shielding effects are found with typical air-flow levels used under clinical conditions. Shielding effects can be avoided by tuning the air flow to the laser repetition rate. |
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Authors:
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Carlos Dorronsoro; Silvia Schumacher; Pablo Pérez-Merino; Jan Siegel; Michael Mrochen; Susana Marcos |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Optics express Volume: 19 ISSN: 1094-4087 ISO Abbreviation: Opt Express Publication Date: 2011 Feb |
Date Detail:
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Created Date: 2011-03-03 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101137103 Medline TA: Opt Express Country: United States |
Other Details:
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Languages: eng Pagination: 4653-66 Citation Subset: IM |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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