## 3 Results
### SEM and EDX Analyses  
Using SEM and EDX analyses, all IOLs of the same group showed similar values; therefore, a single datum is provided for each considered parameter as mean \(\pm\) SD.  
In control IOLs C and O, the basic organic components of PMMA, showed evident peaks (Figures 3A and 4A), with a ratio of 3.5 (Figure 4B).  
In damaged IOLs of both Groups 2 and 3 (Figure 3B), the EDX peaks obtained from Spots \(\alpha\), \(\beta\) and \(\gamma\) were compared with those obtained from the control IOLs surface. As expected, the peak from Spot \(\alpha\) was similar to the control IOLs surface, with no statistical significance for both C and O (\(p=0.29\) and \(p=0.1\), respectively) (Figures 3A and 4A). Their ratio was 3.7 (Figure 4B). This result was reasonable because Spot \(\alpha\) was obtained from an undamaged zone. The EDX spectrum of Spot \(\beta\) showed a significant decrease in C and O contents equal to 82.6% and 75.8% (Figures 3B and 4A) when compared to controls (\(p=0.001\) and \(p=0.001\), respectively), with a significantly reduced ratio of 2.5 (Figure 4B). The intensity of the peaks from Spot \(\gamma\), that is the center of the laser shot, demonstrated a further significant decrease in C and O content (88.9% and 73.5%, respectively), when compared to controls (\(p=0.001\) and \(p=0.001\)) (Figures 3B and 4A), with a significant lower ratio of 1.7 (Figure 4B).  
Furthermore, Spots \(\beta\) and \(\gamma\) showed a significant difference in C content (\(p\) = 0.02), while no difference was observed in O content (\(p\) = 0.55) (Figure 4A). The Al (K\({}_{\alpha}\)) contribution was not considered in all the spectra, as it was related to the specimen holder.  
Figure 2: Scanning electron micrographs of IOLs. (**A**) In Group 1 (control IOLs), at low magnification, the flat shape is well preserved and margins are regular (arrow). (**B**) At higher magnification, the entire surface is regular and smooth. (**C**) In Group 2 (IOLs treated with two laser spots), the shape is still preserved with regular margins (arrow). All along the peripheral part of the IOLs, a hollow furrow with irregular blebs is present (arrowhead), while, in the central part, some straight breaking lines are evident (*). (**D**) At higher magnification, straight breaking lines (*) and a round hole with small radial spokes (open arrowhead) are present. The surface is wrinkled (double arrow). (**E**) Group 3 IOLs (treated with six laser spots) are swollen, empty and broken, owing to the presence of many long irregular fracture lines (arrow). (**F**) At higher magnification, the margins of the lines show a saw-tooth appearance (arrow) and are formed by flat overlapping leaflets of different length (arrowhead). Scale bars: (**A**,**C**,**E**) 1 mm; (**B**,**D**,**F**) 100 \(\upmu\)m.  
Figure 3: Scanning electron microscopy and energy dispersive X-ray spectrometry of IOLs. (**A**) In Group 1 (control IOLs), the presence of C and O is evident. (**B**) In the damaged IOL, three different spots are considered: Spot \(\alpha\) (undamaged surface), Spot \(\beta\) (edge of the surface hit by the laser) and Spot \(\gamma\) (center of the laser injury). Note that Spot \(\alpha\) is comparable with the control IOL spectrum. Spots \(\beta\) and \(\gamma\) show a sharp decrease in C and O contents. Scale bar: 50 \(\mu\)m.