Evaluation of the efficacy of excimer laser ablation of cross-linked porcine cornea.
BACKGROUND
Combination of riboflavin/UVA cross-linking (CXL) and excimer laser ablation is a promising therapy for treating corneal ectasia. The cornea is strengthened by cross-linking, while the irregular astigmatism is reduced by laser ablation. This study aims to compare the efficacy of excimer laser ablation on porcine corneas with and without cross-linking.


RESULTS
The porcine cornea was de-epithelialized and treated with 0.1% riboflavin solution for 30 minutes. A half of the cornea was exposed to UVA-radiation for another 30 minutes while the controlled half of the cornea was protected from the UVA using a metal shield. Photo therapeutic keratectomy (PTK) was then performed on the central cornea. Corneal thickness of 5 paired locations on the horizontal line, ± 0.5, ± 1.0, ± 1.5, ± 2.0, and ± 2.5 mm from the central spot, were measured using optical coherence tomography prior to and after PTK. The ablation depth was then determined by the corneal thickness. There was a 9% difference (P<0.001) in the overall ablation depth between the CXL-half corneas (158 ± 22 µm) and the control-half corneas (174 ± 26 µm). The ablation depths of all 5 correspondent locations on the CXL-half were significantly smaller (P<0.001).


CONCLUSIONS
The efficacy of the laser ablation seems to be lower in cross-linked cornea. Current ablation algorithms may need to be modified for cross-linked corneas.
Affiliated Eye Hospital of Wenzhou Medical College, Lucheng District, Wenzhou, Zhejiang, People's Republic of China.
Shihao
S
Chen
Yini
Y
Li
Aleksander
A
Stojanovic
Jia
J
Zhang
Yibo
Y
Wang
Qinmei
Q
Wang
Theo
T
Seiler
D000818:Animals; D003315:Cornea / Q000601:surgery*; D063171:Corneal Pachymetry; D003432:Cross-Linking Reagents; D054018:Lasers, Excimer; D013552:Swine
D003432:Cross-Linking Reagents