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Heichel J, Wilhelm F, Kunert KS, Schlueter R, Stuhltraeger U, Hammer T. Influence of microkeratome parameters on the stromal bed and flap edge quality in laser in situ keratomileusis. Clin Ophthalmol 2013; 8:61-9. [PMID: 24368878 PMCID: PMC3869919 DOI: 10.2147/opth.s51200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Femtosecond lasers have become the standard for laser-assisted in situ keratomileusis (LASIK) flap creation, but advanced mechanical microkeratomes are still an alternative, more cost-effective way to create the flap. The SCHWIND Carriazo-Pendular microkeratome is one of the most commonly used microkeratomes. The influence of different cutting parameters (head-advance speeds, cutting heads) on morphology of LASIK cuts was investigated. Setting Experimental study performed at the University Eye Hospital of the Martin Luther University Halle/Wittenberg, Halle (Saale), Germany. Methods The Carriazo-Pendular microkeratome was used on freshly enucleated porcine eyes for lamellar keratotomy. After flap removal, the cutting edge and stromal bed were evaluated from scanning electron micrographs using an individualized scoring system. Four different settings of microkeratome parameters were compared. For each setting, eight cuts were evaluated (n=32). Results Different oscillation frequencies and head-advance speeds did not influence the cutting qualities. A higher oscillation/feed rate ratio seemed to be advantageous for a smoother interface. Concerning different cuttings heads, a deeper keratotomy led to sharper cutting edges. The thinner the flap, the more irregularities in the stromal bed appeared. Complications did not occur. Conclusion The Carriazo-Pendular microkeratome is a safe tool with which to create a LASIK flap and is a good alternative to a costly femtosecond laser. Deeper keratotomies, as well as the use of a higher oscillation/feed rate quotient, improve the cutting quality.
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Affiliation(s)
- Jens Heichel
- Department of Ophthalmology, University Hospital of Martin Luther University Halle/Wittenberg, Halle (Saale), Germany
| | | | - Kathleen S Kunert
- Department of Ophthalmology, Helios Klinikum Erfurt, Erfurt, Germany
| | - Rabea Schlueter
- Institute of Microbiology, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Ute Stuhltraeger
- Department of Ophthalmology, University Hospital of Martin Luther University Halle/Wittenberg, Halle (Saale), Germany
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Marian A, Nada O, Légaré F, Meunier J, Vidal F, Roy S, Brunette I, Costantino S. Smoothness assessment of corneal stromal surfaces. J Cataract Refract Surg 2012; 39:118-127. [PMID: 23128030 DOI: 10.1016/j.jcrs.2012.08.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 08/10/2012] [Accepted: 08/12/2012] [Indexed: 11/24/2022]
Abstract
PURPOSE To assess the accuracy of the scanning electron microscopy (SEM) and present alternative approaches to quantify surface roughness based on numerical analysis. SETTING Department of Ophthalmology, Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Quebec, Canada. DESIGN Experimental study. METHODS Lamellar stromal cuts were performed on human corneas using a femtosecond laser or a microkeratome. The photodisrupted stromal surfaces were processed for SEM, and images were acquired at ×1000 magnification. First, images were evaluated by independent observers. Second, images were analyzed based on first-order and second-order statistics of gray-level intensities. Third, 3-dimensional (3-D) surface reconstructions were generated from pairs of SEM images acquired at 2 angles. RESULTS Results show that traditional assessment of roughness based on evaluating SEM images by independent observers can be replaced by computer-image texture analysis; an algorithm was developed to avoid subjective and time-consuming observations. The 3-D reconstructions allowed additional characterization of surface properties that was not possible with SEM images alone. Significant fluctuations in surface height were lost, although they could be retrieved using 3-D reconstructions. CONCLUSIONS Image texture analysis allowed objective and repeatable assessment of stromal surface roughness; however, full assessments of surface-height fluctuations required 3-D reconstruction. These complementary methodologies offer a more comprehensive assessment of corneal surface roughness in clinical applications.
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Affiliation(s)
- Anca Marian
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada
| | - Ossama Nada
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada; The Ophthalmology Department Ain Shams University, Cairo, Egypt
| | - François Légaré
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada
| | - Jean Meunier
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada
| | - François Vidal
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada
| | - Sébastien Roy
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada
| | - Isabelle Brunette
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada
| | - Santiago Costantino
- From the Maisonneuve-Rosemont Hospital Research Center (Marian, Nada, Brunette, Costantino), the Department of Mathematics and Statistics (Meunier, Roy), University of Montreal, and the Department of Ophthalmology (Meunier, Brunette, Costantino), University of Montreal, Montreal, Quebec, and the Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (Marian, Légaré, Vidal), Varennes, Quebec, Canada.
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