近视性屈光不正LASIK手术前后对比敏感度的临床研究

Contrast sensitivity of myopic patients before and after laser in situ keratomileusis surgery

目的:通过计算机对比敏感度检查仪对近视性屈光不正行准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)手术前后的空间对比敏感度进行检查,以探讨LASIK手术前后对比敏感度的变化情况。方法:对51例(101眼)LASIK手术患者术前进行常规的准分子激光术前检查、最好矫正视力和空间对比敏感度检查,并按近视的度数分为高度近视组和中低度近视组。LASIK手术后第1d,在裂隙灯显微镜下判断有无角膜微纹,并依据其进行进一步分组。分别检查术后0.5,1和3mo的最好矫正视力和空间对比敏感度。结果:LASIK术后0.5mo,虽然有99%的病例术后矫正视力达到5.0以上,但对比敏感度在各个空间频率上都有统计学意义上明显的下降(P<0.05)。术后1mo,中低度近视组对比敏感度在各个空间频率上有明显恢复,可达到术前水平。高度近视组术后1mo在中低空间频率上可恢复至术前水平,但在高频上(8,16cpd)较术前仍有统计学意义上明显下降,直至术后3mo仍不能恢复至术前水平(P<0.05)。有角膜微纹组对比敏感度下降较为明显,直至术后3mo,除了低空间频率的1cpd外,其他各个空间频率上均有统计学意义(P<0.05)的减退。结论:对比敏感度和传统的视力检查相比,能反映出检查眼在不同对比度下的视功能情况,更加接近日常生活中视觉需求。LASIK术后对比敏感度会出现暂时下降,并随着时间的推移逐渐恢复。高度近视和角膜微纹的病例术后对比敏感度恢复较慢。

AIM： To evaluate the changes of spatial contrast sensitivity by computer program before and after laser in situ keratomileusis （LASIK） surgery for myopia. METHODS： A total of 51 patients （101 eyes） who underwent LASIK were divided into two groups（ 〈 6.00D and 〉16.00D）. Best corrected visual acuity measured by the Snellen visual acuity chart and spatial contrast sensitivity were tested before and at two weeks, one month and three months after LASIK surgery. Corneal microstriae were diagnosed under slit-lamp microscope on the first day after LASIK. RESULTS： Although 99% of patients had best corrected visual acuity 〉 5.0, the contrast sensitivity at all spatial frequencies had a significant decline in all patients at two weeks after LASIK （ P 〈 0.05）. The contrast sensitivity of low and moderate myopia group （〈 6. 00D） had a remarkable recover at all spatial frequencies and approached to the preoperative level at one month after LASIK, while the contrast sensitivity of high myopia group （〉16.00D） may reach the preoperative level at low and medium spatial frequencies and had a significant decline at high spatial frequency （8,16cpd） at 1 month after LASIK and could not recover to the preoperative level even at 3 months after LASIK （ P 〈 0.05）. There was a significant reduction in the spatial contrast sensitivity at all spatial frequencies in the subgroup which had corneal microstriae except at lcpd at 3 months after LASIK. CONCLUSION： Compared with the traditional Snellen visual acuity, contrast sensitivity can reflect the visual function under different contrasts. The contrast sensitivity had a temporary decline after LASIK but could recover with time going by. Moreover, the contrast sensitivity of high myopia patients and patients with corneal microstriae recovered slowly.