Evaluation of the Efficacy of Excimer Laser Ablation of Cross-Linked Porcine CorneaReport as inadecuate




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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.

Methods and Findings

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.

Conclusion

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.



Author: Shihao Chen, Yini Li, Aleksander Stojanovic, Jia Zhang, Yibo Wang, Qinmei Wang , Theo Seiler

Source: http://plos.srce.hr/



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