Amm M, Wetzel W, Winter M, Uthoff D, Duncker G I
Kiel University Eye Hospital, Germany.
J Refract Surg. 1996 Nov-Dec;12(7):758-66. doi: 10.3928/1081-597X-19961101-07.
After 193 nm excimer laser photorefractive keratectomy (PRK) for myopia, superficial opacities in the ablation zone and regression of refractive results can occur. Clinical studies have emphasized that corneal clarity and early refractive stability can be achieved with laser in situ keratomileusis (LASIK). We present clinical and histological results that compare PRK and LASIK for the treatment of myopia in rabbits.
We treated 12 New Zealand white rabbits with PRK and 12 with LASIK using a 193-nm excimer laser (Aesculap Meditec). In both techniques, the identical excimer software and ablation parameters of -10 D treatment depth were used. Six months after surgery, all eyes were removed and prepared for light, fluoresence and transmission electron microscopy.
At the time of enucleation, nine eyes in the PRK group had a moderate to high degree of haze (grade 2 to 3), whereas after LASIK, all corneas showed an almost clear interface in the ablation zone. Correspondingly, all histological investigations after LASIK showed a regular stromal architecture, in contrast to the obvious anteri or stromal disorganization after PRK.
The preserved integrity of the superficial corneal layers after LASIK ensures quick wound healing with minimal tissue proliferation, resulting in a transparent corneal interface. This technique appears especially suitable for correcting high myopia.
193纳米准分子激光屈光性角膜切削术（PRK）治疗近视后，切削区可能会出现浅层混浊，屈光结果也会回退。临床研究强调，准分子原位角膜磨镶术（LASIK）可实现角膜透明及早期屈光稳定。我们展示了比较PRK和LASIK治疗兔近视的临床及组织学结果。
我们用193纳米准分子激光（蛇牌美迪泰克公司）对12只新西兰白兔行PRK治疗，另12只行LASIK治疗。两种技术均使用相同的准分子软件及-10D治疗深度的切削参数。术后6个月，摘除所有兔眼，准备进行光镜、荧光及透射电镜检查。
摘除眼球时，PRK组9只眼有中度至高程度的 haze（2至3级），而LASIK术后，所有角膜在切削区均显示几乎透明的界面。相应地，LASIK术后所有组织学检查均显示基质结构规则，与之形成对比的是，PRK术后前基质明显紊乱。
LASIK术后角膜浅层的完整性得以保留，确保伤口快速愈合，组织增殖最少，从而形成透明的角膜界面。该技术似乎特别适合矫正高度近视。
