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K. Hong, S. Chang; The Size of Barron Punch Corresponding to the Diameter of Lamellar Flap Prepared by Conventional Femtosecond Laser (IntralaseTM) for Descemet Stripping Endothelial Keratoplasty. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2210.
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© ARVO (1962-2015); The Authors (2016-present)
The diameter of the Descemet-stripping endothelial keratoplasty (DSEK) flap which is cut with a femtosecond laser (IntralaseTM), corresponds to the length of an arc of a fan-shape, and the size of the corneal punch that cuts the endothelial flap vertically corresponds to the length of a chord of a fan-shape. We calculated these two values mathematically, then compared them against the measured values in an experimental pig cornea.
Considering the corneal curvature, the corneal diameter of the posterior lamellar flap (which is obtained by a IntralaseTM) was set to the length of an arc of a fan-shape when the cornea was returned to its original contour. The length of a chord corresponding to an arc was obtained using the trigonometric function. The length of the chord obtained was set at the maximum diameter of the corneal punch that can be used. The length of the arc, corresponding to the diameter of the corneal punch, was obtained using the trigonometric function. The arc length was set to the minimum diameter of the DSEK flap which was made by a IntralaseTM.
When the corneal curvature was 43.5 D, the donor cornea underwent lamellar dissection at a thickness of 400 µm and the endothelial lamellar flap cuts were 8.0 mm, 8.5 mm, 9.0 mm and 9.5 mm, the corneal punch diameters needed to be smaller than 7.612 mm, 8.035 mm, 8.449 mm and 8.854 mm respectively. For corneal punches with diameter 9.0 mm, 8.5 mm, and 8.0 mm, the diameter of the femtosecond laser-assisted DSEK flap needed to be larger than 9.683 mm, 9.061 mm, and 8.457 mm respectively.
When an endothelial lamellar flap is made using a femtosecond laser and a corneal punch, the appropriate DSEK transplantation flap size can be determined if the diameter of the corneal flap obtained by a IntralaseTM corresponding to the diameter of the corneal punch can be predicted
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