variations within endothelial grafts for DSAEK 厚度变化范围内的内皮移植角膜内皮移植术ppt课件.pptVIP

Thickness variations within endothelial grafts for DSAEK surgery. A spectral domain anterior segment OCT study;DSAEKDescemet Stripping Automated Endothelial Keratoplasty;The normal cornea is thicker in the periphery and thinner in the center. Tissue harvesting with microkeratome and femtolaser, that measure lamellar thickness from epithelial surface, creates regular lamellae for anterior keratoplasty techniques, but the remaining endothelial lamellae, that are the one used for DSAEK, necessarily change in thickness from center to periphery. ;PURPOSE;MATERIALS and METHODS;ANALYSIS;Casia? Flap Tool: Measurement of Total Corneal Thickness + Flap thickness ;RESULTS: Thickness variability along meridians;SD of the thickness values at 1.5mm of eccentricity ranged between 5,2% and 18,9% of central thickness and mean SD was 11,4% of central thickness. At 3mm, thickness SD range was: 8,4 - 29,6 % of central thickness (mean SD = 17%) ;CONCLUSIONS: thickness variation ALONG MERIDIANS;We found also a significant variability of graft thickness at a given eccentricity: at 1,5 mm ? SD of 11,4 %; at 3 mm ? SD of 17,0 % Flap thickness variability can be caused by Irregularity of the cut Misalignment of the thinnest point of the donor cornea with the optical center, that can be caused by: Not-centered microkeratome cut Not-centered punching Not-centered adhesion of the graft … moreover, optical center can be different from geometrical center ;Further work is needed to clarify the optical effects of this variability in flap thickness. Fortunately little difference exists between the optical constants of the cornea and acqueous umor, reducing optical aberrations linked to graft irregularities. THANK YOU FOR YOUR ATTENTION!