Evaluation of the Efficacy of Excimer Laser Ablation of Cross-Linked Porcine Cornea |
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Authors: | Shihao Chen Yini Li Aleksander Stojanovic Jia Zhang Yibo Wang Qinmei Wang Theo Seiler |
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Institution: | 1. The Affiliated Eye Hospital of Wenzhou Medical College, Lucheng District, Wenzhou, Zhejiang, People''s Republic of China.; 2. Eye Department, University Hospital of North Norway and Synslaser Kirurgi AS, Tromsø, Norway.; 3. Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland.; University of Reading, United Kingdom, |
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Abstract: | BackgroundCombination 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.Methods and FindingsThe 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).ConclusionThe 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. |
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