4. Results
The surgery was uneventful in all cases. No tears or incomplete procedures were recorded. Five anterior lens capsules were created by the LenSx laser, five samples were obtained using the Victus laser, and five samples were obtained by manual CCC.
The LenSx capsulotomy cutting edges showed a postage stamp like pattern, with several bumps and notches of variable width, ranging between 3 and 10 μm, that were spread across the edge (Figures 1, 2 and 3). Linear cracks (length ranging between 4 and 9 μm; width < 3 μm) were also seen across the edges. The Victus capsulotomy cutting edges showed micro-can opener structure; nevertheless the stacks of collagen fibers could be seen at the capsular edges in some specimens (Figures 1, 2 and 3). Linear cracks (width < 3 μm) and notches (width ranging between 3 and 9 μm) were also seen at the capsular edge. The manual CCC cutting edges showed clear stacks of collagen fibers (Figure 4). The edges were smooth and regular in all cases. No microdiscontinuities of the edge were seen in any case.
Figure 1
(a), (b) The Victus and LenSx capsulotomy cutting edges are shown, respectively. Linear cracks (black arrow) and tags (white arrow) are spread across the edges. The generation of these features may be consistent with eye movements during laser capsulotomy.
Figure 2
(a), (b) The Victus and LenSx capsulotomy cutting edges are shown, respectively. The microirregularities at the capsular edge are a direct consequence of the FS laser photodisruptive effects. Bumps (black arrows) and notches (white arrows) were spread across the cutting edges, giving rise to a variable pattern, ranging from a can opener to a postage stamp-like structure, that are consistent with cavitation and thermal effects of FS laser on the capsule microstructures.
Figure 3
(a), (b) High-magnification images of the Victus and LenSx capsulotomy cutting edges, respectively. The stacks of collagen fibers at the capsular edge could be seen in some specimens (3/5) treated by the Victus FS laser. This was not the case for the LenSx specimens, likely related to a high thermal effect excerpted on the collagen fibers.
Figure 4
(a), (b) Two manually torn capsules are shown. The stacks of collagen fibers are clearly shown at the edge of the capsule. The edge morphology is smooth, with no irregularity. (c), (d) High-magnification images of the manual CCC edges are shown in (a) and (b), respectively.
The manual CCC had statistically significantly smoother cutting edges than FS laser capsulotomies, as summarized in Table 1. Both the Sa and the Sq values were statistically significantly lower (P < 0.05) in manual CCC than in FS capsulotomy cutting edges. There were no differences in Sa and Sq values (P > 0.05) between the two FS laser platforms. The distribution of data showed moderate skewness, with average values ranging between 0.35 and 0.62 across specimens. No significant differences in Ssk values (P > 0.05) were found between the FS laser capsulotomies and the manual CCC cutting edges, however, with the laser-cut capsules showing high intersample variation. The Sku values were less positive (Victus) or showed negative values (LenSx), in the FS laser samples, indicating a flatter height distribution than manual CCC.
Table 1
Irregularity analysis (mean ± SD) of the FS laser capsulotomy and manual CCC cutting edges.
| Sa (µm)* | Sq (µm)* | Ssk (no unit) | Sku (no unit) | |
|---|---|---|---|---|
| LenSx capsulotomies (n = 5) |
5.98 ± 0.56 | 1.18 ± 0.24 | 0.35 ± 0.24 | −0.43 ± 0.63 |
| Victus capsulotomies (n = 5) |
6.49 ± 0.33 | 1.32 ± 0.16 | 0.63 ± 0.24 | 0.00 ± 0.42 |
| Manual CCC (n = 5) |
4.94 ± 0.56 | 0.57 ± 0.13 | 0.39 ± 0.14 | 0.44 ± 0.65 |
*Statistically significant differences between groups: P < 0.05.
In manual CCC, the LEC boundary was close to the cutting edge, with mean distance of 12 ± 8 μm. It was on average 40 ± 9 μm far from the laser capsulotomy cutting edge, with no differences between the FS laser platforms.