Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Opthalmology

Purpose: To analyze and compare the structure and regularity of capsulotomy cutting edges, and to assess the accuracy of the reproducibility of the centration and size of capsulotomy in both groups. Methods: Twenty anterior capsulotomies were obtained using FS laser cataract platform (Catalys, {u1D45B} = 20) group A .In addition, twenty manual CCC ({u1D45B} = 20) group B, were obtained using a rhexis forceps. The specimens were imaged by eSEM (Quanta FEG 250, Czech Republic), and were processed and analyzed using Image-Java software (version 1.5). Irregularity of the capsule edges were analyzed morphologically and quantified using 8 parameters; the arithmetic mean deviation of the surface (Sa),the root-mean-square deviation of the surface (Sq), the skewness of the topography height distribution (Ssk), the kurtosis of the topography height distribution (Sku), contrast, angular second moment, coefficient of variation (CoV), and the gray-level co-occurrence matrix measurements (Homogeneity). Centration and size of the capsules were also analyzed. Effective phacoemulsification power and time were evaluated and compared between both groups as secondary outcomes. Results: By SEM, morphologically the femtosecond laser{u2013}assisted capsulotomy edge surfaces showed marked irregularity compared with the smooth edge of the CCC. The edges of manually torn capsules were shown, by comparison of Sa and Sq values, to be smoother ({u1D443} = 0.01) than the FS laser capsulotomy edges. The Ssk values were lower in group A compared to group B (1.28 ± 0.17 vs.1.35 ± 0.17, P= 0.08).Similarly the Sku were also lower in group A than group B (2.14 ± 1.12 vs. 2.55 ± 1.11, P = 0.08). The angular second moment (P =0.01) and contrast (P =0.04) measures for both lasers differed significantly from those obtained for CCC .Although the laser capsulotomy edges were rougher ( 109.31 ± 2.40) than the manual capsulorhexes (110.93 ± 3.92) , the mean CoV values from the regression analysis was not statistically significant for bothhorizontal meridianeducing effective phacoemulsification time and power during lens fragmentation

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