Low_resolution_Thesis_CDD_221009_public - Visual Optics and ...

METHODS
Fig. 2. 9. Set of points in corneal polar coordinates where elevation data are given by
the videokeratoscope.
Corneal videokeratoscopy was compared with Talysurf contact profilometry on
ablated spherical surfaces of PMMA. Fig. 2. 10 shows data of the laser ablation on a
8-mm sphere (with the laser system described in Chapter 3), for a -3D ablation. The
base sphere has been substracted to the measurements. Confocal microscopy with
Plwas also performed, although only in the central 4 mm. The three techniques
provided estimates of the apical radius of curvature (in the post-ablated surface) within
0.01 mm, and estimates of the asphericity within 0.02. The ablation depth estimated
from the difference pre/post ablation topographies varies less than 2 microns across
the three methods.
Fig. 2. 10. Comparison between videokeratoscopy (red) and contact profilometry
(green) for an ablation of -3 D in a PMMA spherical surface. Confocal microscopy
with Plis also shown (blue points). The discrepancy in apical radius and asphericity
is below 0.01 mm and 0.02. The difference in ablation depth is less than 2 microns.
The base spphere has been substracted from the measured elevation maps.
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