摘要
目的 比较准分子激光角膜切削术 (photorefractivekeratectomy ,PRK)与准分子激光原位角膜磨镶术 (laserinsitukeratomileusis,LASIK)后激光对角膜组织的切削效应及角膜的愈合情况 ,从组织学角度探讨角膜雾状混浊 (Haze)及屈光度数回退的成因。方法 2 4只新西兰白兔按预矫屈光度数随机分为 - 4 0 0D组和 - 8 0 0D组 ,每只兔右眼行PRK ,左眼行LASIK。术后 10d ,1、3及 6个月观察Haze情况并验光 ,每组随机处死 3只兔取角膜行光镜、电镜及免疫组化检查 ,检测胶原Ⅲ、胶原Ⅳ、纤维连结蛋白 (fibronectine,FN)及转化生长因子 β1(transforminggrowthfactor β1,TGF β1)的含量。结果 行PRK术的右眼术后出现不同程度的Haze及屈光度数回退 ,其程度与预矫正屈光度数成正比。行LASIK术的左眼术后除少数角膜瓣周围半环形混浊外 ,手术区域角膜透明 ,屈光度数回退较右眼轻。- 4 0 0D组右眼与左眼术后屈光度数均稳定 ,- 8 0 0D组右眼较左眼屈光度数回退明显。右眼术后角膜愈合反应重 ,恢复慢。6个月时角膜基质仍处于修复阶段。左眼术后除形成角膜上皮栓及对应处基质轻度增生外 ,手术区域角膜瓣与基质床间界面清晰 ,无明显增生 ,角膜基质愈合反应轻、恢复快。术后所有兔眼角膜均有TGF β1表达及活化 ,持续时间与?
Objective To compare effects of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) on the cornea and corneal wound healing and to investigate the possible mechanism of corneal haze and myopic regression histopathologically. Methods Twenty-four New Zealand white rabbits were allocated randomly to correct -4.00 and -8.00 diopters and were operated with PRK on right eyes and LASIK on left eyes. At 10 days and 1, 3, and 6 months, corneal haze was observed, refraction was evaluated, and 3 rabbits were randomly selected for each time point to be enucleated, and corneas to be bisected. One half of each cornea was evaluated using transmission electron microscopy, and the other half was evaluated using either light microscopy or immunohistochemical staining for collagen type Ⅲ, Ⅳ, fibronectin (FN) and transforming growth factor-β 1 (TGF-β 1). Results Different degrees of corneal haze and myopic regression were observed after PRK: the higher the desired myopic correction, the heavier the haze. Corneal wound healing response was greater and lasted longer after PRK than after LASIK. Various pathological findings such as epithelial hyperplasia, basal membrane reforming and extracellular matrix deposits were found in the ablation zone and repair mechanisms were still active at 6 months after PRK. Whereas after LASIK, the interface between the flap and stromal bed was transparent except for growing epithelial plugs and lightly proliferating stroma coinciding with the flap margins. After both PRK and LASIK, all corneal cell types were consistently positive for TGF-β 1 antibody during the corneal wound healing time. TGF-β 1 antibody positivity decreased as the wound healing approached completion. The histopathological changes of corneal haze and myopic regression are as follows: epithelial hyperplasia, basal membrane immaturity, anterior stromal keratocyte increase and activity, new collagen Ⅲ production and irregular arrangement thereof, and FN deposition in the extracellular matrix under the epithelium. Conclusions Compared with PRK, LASIK ensures refractive stability with quick wound healing and minimal tissue proliferation resulting in a more promising corneal refractive surgery to correct myopia, especially more severe cases of myopia. The corneal wound healing especially the stromal healing is the key to the cause of haze and myopic regression. TGF-β 1 may be involved in scar formation during wound healing by stimulating expression of collagen Ⅲ and FN and is believed to be an important regulating factor.
出处
《中华眼科杂志》
CAS
CSCD
北大核心
2003年第3期140-145,共6页
Chinese Journal of Ophthalmology
关键词
准分子激光
角膜切削术
角膜磨镶术
角膜创口
PRK
Cornea
Keratectomy, photorefractive, excimer laser
Keratomileusis,laser in situ
Wound healing
Animals, laboratory
