Fig. 17.1
Electron microscopy and ImageJ analysis – overview pictures (a, bar = 50 μm) were taken to select areas with cross cut collagen fibres. A single keratocyte can be detected in this overview (arrow). Higher-resolution pictures were used for analysis (b, bar = 200 nm). Using ImageJ single collagen fibres were circled (upper right panel), filled (lower right panel) and counted (background picture and higher resolution down left) (With kind permission from Klinische Monatsblätter für Augenheilkunde.)
The main findings of the study are as follows:
(a)
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Intraoperative lenticule dissection difficulties
Nine out of the 30 lenticules were difficult to dissect. The difficulty of lenticule dissection was determined on the basis of surgical video analysis prior to statistical analysis.
A thicker collagen fibre diameter involves a potential risk for increased intraoperative lenticule adhesiveness (p = 0.056). Vice versa a higher fibre distance and a lower fibre density, respectively, significantly reduce the risk of intraoperative difficulty in dissecting a lenticule (p = 0.036); see Fig. 17.2. Furthermore, a higher coefficient of variation (CV) of fibre density also seems to reduce the risk for lenticule adhesiveness (p = 0.033).
Fig. 17.2
Correlation of intraoperative lenticule separability and fibre distance and its coefficient of variation, respectively. The correlation of intraoperative difficult lenticule separability and collagen fibre distance (a) and coefficient of variation (CV) of fibre density (b) showed significant findings