Figure 1.
Porcine eye was mounted in a fixation device throughout the experiment.
Each eye was mounted in a fixation device throughout the experiment. A 9.0 mm suction ring with a cross-mark was applied to the eye and centered on the corneal apex to avoid eye rotation. The vertical mark (black arrow) on the suction ring separated the cornea into CXL-half and control-half, while the horizontal line (white arrow) on the suction ring represented the direction along which the CT was measured. The intersection (red spot) of the two lines (dotted lines, invisible) was used as the center spot of pachymetry and laser ablation. In this picture, riboflavin solution (yellow colored) filled within the suction ring and formed a thin and intact film over the de-epithelialized cornea throughout the CXL procedure.
Figure 2.
Porcine eye underwent UVA-irradiation with half of the cornea sheltered by a metal shield.
During the irradiation, one half of the cornea was sheltered with a metal shield (MS) (without contact) so that only the uncovered half (C) was irradiated and cross-linked. The edge of the shield was in accordance with the vertical line on the suction ring (R). Only part of the horizontal line (black arrow) could be seen.
Figure 3.
Pachymetry was taken along the horizontal line of the suction ring using OCT. CT was measured on that meridian at 5 pairs of equidistant locations, ±0.5, ±1.0, ±1.5, ±2.0, and ±2.5 mm from the central spot, using the RTVue's “flap tool” in the CL-line scan.
Figure 4.
Demarcation line observed after laser ablation.
A distinct demarcation line was observed between CXL-half (left) and control-half (right) after excimer laser ablation, with the former showing lower reflectivity.
Figure 5.
Mean ablation depth of 30 eyes at the five correspondent locations.
The horizontal axis represented the measured location of the cornea, the vertical axis represented the ablation depth. The solid line represented the CXL group that was less ablated. The dotted line represented the control group that was more ablated. The peripheral locations appeared to be more ablated than central locations.
Table 1.
Average ablation depths in the 5 paired locations.