飞秒激光在角膜手术中的应用

Femtosecond laser's application in the corneal surgery

1990年代,一种新型的超短超快激光—飞秒激光(femtosecond laser,FS)出现并开始应用于各个领域。飞秒激光是一种以超短脉冲形式运转的近红外光。1飞秒等于千万亿分之一秒(1×10-15s)。如此快的脉冲激光很少将热量和振动传导至周围组织,从而较少引起周围组织的损伤。随着技术的发展,开始出现应用飞秒激光制作角膜板层瓣,即飞秒激光辅助下的准分子激光角膜原位磨镶术,后来,其应用于飞秒激光辅助下的角膜移植术、角膜基质环植入术。飞秒激光进行角膜移植手术,主要是应用飞秒激光可以制作角膜植片和植床,准确切割各层病变角膜组织,即使在轻度的角膜斑翳和角膜水肿时,也可以达到部分切割的目的。

With the rapid development over the past two decades, femtosecond （ 10-15 s ） lasers （ FS ） has become a new application in ophthalmic surgery. As laser power is defined as energy delivered per unit time, decreasing the pulse duration to femtosecond level （ 100fs ） not only increases the power delivered but also decreases the fluence threshold for laser induced optical breakdown. In ablating tissue, FS has an edge over nanosecond lasers as there is minimal collateral damage from shock waves and heat conduction during surgical ablation. Thus, application of FS has been widely spread, from flap creation for laser-assisted in situ keratomileusis （ LASIK） surgery, cutting of donor and recipient corneas in keratoplasty, creation of pockets for intracorneal ring implantation. FS applied in keratoplasty is mainly used in making graft and recipient bed, and can exactly cut different tissue of keratopathy. FS can also cut partial tissue of cornea, even if it is under the moderate corneal macula and corneal edema condition.