准分子激光近视矫正术后亮环境下对比度视力变化的观察

Changes of contrast visual acuity under photopic environment following excimer laser corneal refractive surgery

  • 摘要: 目的 研究准分子激光近视矫正术后对比度视力恢复情况,观察中低度近视患者行飞秒激光原位角膜磨镶术(femtosecond laser-assisted in situ keratomileusis,FS-LASIK)或准分子激光上皮瓣下角膜磨镶术(laser assisted subepithelial keratomileusis,LASEK)前后亮环境下对比度视力的变化情况。 方法 随机选取行FS-LASIK及LASEK术的中低度近视患者各20例,以手术右眼为受检眼,共40眼,等效球镜度为-1.00 ~ -5.00D,使用MFVA-100多功能电子视力检查仪(深圳亮睛公司),选定100%、25%、10%、5%四个固定的对比度,通过控制监视器程序,屏幕上E型单个视标随机出现,分别检查右眼在术前、术后1周、术后1个月及术后3个月亮环境下不同对比度视力。 结果 FS-LASIK组:5%对比度视力术后1周(0.473±0.230)与术前(0.291±0.088)相比降低(P< 0.05),术后1个月(0.290±0.095)、3个月(0.271±0.115)与术前差异无统计学意义(P> 0.05);100%、25%、10%对比度视力与术前相比在各个时期差异均无统计学意义(P> 0.05)。LASEK组:术后1周,不同对比度视力与术前相比均下降(P< 0.05);术后1个月5%对比度视力(0.589±0.224)未恢复术前水平(0.405±0.118)(P< 0.05),其他均已恢复;术后3个月5%对比度视力(0.405±0.117)与术前相比无统计学差异(P> 0.05)。 结论 轻中度近视准分子激光角膜屈光手术患者,术后早期低对比度视力下降明显,尤其是LASEK术。两种术式术后3个月对比度视力恢复正常,5%低对比度视力可以作为术后视觉质量的评价指标。

     

    Abstract: Objective To investigate the changes of contrast visual acuity (CVA) under photopic environment in patients with low/moderate myopias treated by femtosecond laser-assisted in situ keratomileusis (FS-LASIK) versus laser assisted subepithelial keratomileusis (LASEK). Methods The FS-LASIK group and the LASEK group consisted of 20 right eyes (20 patients) respectively.The spherical equivalent ranged from -1.00 to -5.00 D. The patients were tested with multi-functional visual acuity tester-100(MFVA-100) at 4 contrast levels (100%, 25%, 10%, 5%) before operation and at 1 week, 1 month, 3 months after operation. Results As for the FS-LASIK group, 5% CVA at 1 week after operation was significantly lower than that before operation under photopic environment (0.473±0.230) vs (0.291±0.088), P< 0.05, but the levels at 1 month and 3 months after operation showed no statistically significant difference compared with the preoperative (0.290±0.095) and (0.271±0.115) vs (0.291±0.088), P> 0.05, and there was no statistically significant difference in 100%, 25%, 10% CVA before and after operation at different time points (P> 0.05). As for the LASEK group, CVA at each constrast level at 1 week after operation decreased compared with before operation (P < 0.05), 5% CVA at 1 month after operation did not returned to the preoperative level (0.589±0.224) vs(0.405±0.118), P< 0.05, and there was no statistically significant difference in 5% CVA before and at 3 months after operation(P> 0.05). Conclusion In mild-to-moderate myopic patients underwent excimer laser corneal refractive surgery, low contrast visual acuity (LCVA) decreases obviously in the early postoperative period. The CVAs of FS-LASIK group and LASEK group return to the preoperative level at 3 months after surgery. 5% CVA can be used as an evaluating indicator of postoperative visual quality.

     

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