Moilanen Jukka A O, Vesaluoma Minna H, Müller Linda J, Tervo Timo M T
Department of Ophthalmology, University of Helsinki, Finland.
Invest Ophthalmol Vis Sci. 2003 Mar;44(3):1064-9. doi: 10.1167/iovs.02-0247.
To examine human corneal morphology and nerve recovery 5 years after photorefractive keratectomy (PRK).
Fourteen eyes of 14 patients (ages, 27-53 years) who underwent 6-mm diameter PRK for low to moderate myopia (spherical equivalent [SE] -2.5 to -8.0 D) were examined once 5 years after surgery. Nine healthy individuals served as control subjects. Standard biomicroscopy, manifest refraction, and visual acuity tests were performed. The morphology of the corneas was examined by in vivo confocal microscope. Thicknesses of the epithelium and stroma, as well as the density of corneal opacity (haze) were obtained from digital image analysis of the confocal microscopy through-focusing (CMTF) scans.
Confocal microscopy revealed increased reflectivity in the subepithelial extracellular matrix, keratocyte nuclei and processes in all patients. The mean objective haze estimate was 166.7 U (range, 50-390) in control corneas compared with a mean of 225.9 U (range, 125-430, P = 0.15) in the post-PRK corneas. The density of the subbasal nerve fiber bundles in post-PRK corneas (mean, n = 4.2; range, n = 1-7 per field of view) was not significantly lowered from that in control subjects (mean, n = 4.9; range, n = 3-6; P = 0.56). Bowman's layer was undetectable in all post-PRK corneas. Clinically, slit-lamp-observed trace of haze in four corneas correlated positively with the ablation depth (P = 0.016) and the thickness of the haze area (P = 0.006) in the confocal microscope.
In vivo confocal microscopy demonstrates the presence of morphologic alterations even 5 years after PRK. However, these alterations are overcome by cellular and neural recovery and do not seem to interfere with visual performance.
研究准分子激光原位角膜磨镶术（PRK）5年后的人眼角膜形态及神经恢复情况。
对14例（年龄27 - 53岁）接受直径6mm PRK治疗低度至中度近视（等效球镜度[SE] -2.5至-8.0 D）的患者的14只眼在术后5年进行一次检查。9名健康个体作为对照。进行了标准生物显微镜检查、显验光和视力测试。通过活体共聚焦显微镜检查角膜形态。上皮和基质厚度以及角膜混浊（ haze）密度通过共聚焦显微镜聚焦扫描（CMTF）的数字图像分析获得。
共聚焦显微镜显示所有患者的上皮下细胞外基质、角膜细胞的细胞核和突起的反射率增加。对照角膜的平均客观 haze估计值为166.7 U（范围50 - 390），而PRK术后角膜的平均估计值为225.9 U（范围125 - 430，P = 0.15）。PRK术后角膜的基底神经纤维束密度（平均，n = 4.2；范围，每个视野n = 1 - 7）与对照受试者相比无显著降低（平均，n = 4.9；范围，n = 3 - 6；P = 0.56）。所有PRK术后角膜均未检测到Bowman层。临床上，裂隙灯观察到4只角膜有微量 haze与共聚焦显微镜下的消融深度（P = 0.016）和 haze区域厚度（P = 0.006）呈正相关。
活体共聚焦显微镜显示即使在PRK术后5年仍存在形态学改变。然而，这些改变被细胞和神经恢复所克服，似乎并未干扰视觉性能。
