角膜瓣论文：角膜瓣波前像差对比敏感度飞秒激光

角膜瓣论文：角膜瓣 波前像差 对比敏感度 飞秒激光

【中文摘要】背景和准分子激光原位角膜磨镶术是目前矫正屈光不正的主流手术。它的步骤是先在角膜上用特制的微型角膜板层刀做一个带蒂的角膜瓣,掀开角膜瓣后,在暴露的角膜基质床上进行准分子激光消融,以矫正近视、远视、散光。该手术的优点是保留了角膜上皮及前弹力层的完整性,疗效显著、术后视力恢复快。该手术的缺点是首先在角膜表面制作角膜瓣,术中因使用微型角膜板层刀制作角膜瓣而导致的并发症不可忽视,严重的并发症影响术后的视觉质量,因此角膜瓣的成功关乎手术的成败。飞秒激光是一种以脉冲形式运转的激光,持续时间非常短,只有几个飞秒,是人类目前在实验室条件下所能获得的最短脉冲,目前用于角膜手术的波长为1053nm。由于它能对角膜组织进行高精确的切割,而且不影响切割区以外的组织,具有极高的安全性,因此近年来被逐渐应用到眼科领域,尤其是准分子激光手术中角膜瓣的制作已经取得了巨大的成功。研究微型角膜板层刀制瓣与飞秒激光制瓣两种不同的制瓣方式对视觉质量的影响,对临床选择制瓣方式有应用价值。本文通过研究比较飞秒激光制瓣与微型角膜板层刀制瓣两种不同制瓣方式对术后视觉质量的影响,评价飞秒激光制瓣术后的角膜瓣质量及视觉质量。方法随机选取2009年11月至2010年4月在我院眼科准分子激光中心双眼行LASIK的近视患者100例(200眼)分为两组：飞秒组、板层刀组,飞秒组使用Femto LDV飞 秒激光(瑞士Ziemer公司)制作角膜瓣,板层刀组使用Hansatome板层刀(美国博士伦公司)制作角膜瓣,两组除制作角膜瓣方式不同外,均采用同一台准分子激光机Technolas 217Z100(美国博士伦公司)进行波前像差引导的准分子激光切削。于术后1月使用傅立叶域光学相干断层扫描前节角膜模块测量两组实际角膜瓣厚度、均匀程度,于术后1周、1月、3月复查视力、波前像差、对比敏感度。采用SPSS16.0统计分析软件对实验数据进行合理的统计和分析。以α=0.05作为检验标准。结果1角膜瓣测量：飞秒激光组预计110μm角膜瓣实际平均厚度为103.54±5.60(88-131)μm,实际厚度与预计厚度之间比较差异无统计学意义(P>0.05)；其中先做眼(右眼)平均角膜瓣厚度102.17±4.80μm,后做眼(左眼)平均角膜瓣厚度104.42±4.97μm,左右眼之间比较差异无统计学意义(P>0.05)。板层刀组预计110μm角膜瓣实际平均厚度130.30±14.03(90-158)μm,实际厚度与预计厚度之间比较差异有统计学意义(P0.05)；术后不同时间段,板层刀组总高阶像差、3阶垂直彗差增加大于飞秒组,差异有统计学意义(P0.05)；暗视状态下,飞秒组术后1周,在12.0c/pd、18.0 c/pd优于板层刀组,差异有统计学意义(P0.05)；明视眩光状态下,相同时间段两组各空间频率比较差异无统计学意义(P>0.05)；暗视眩光状态下,飞秒组术后1周,各空间频率优于板层刀组,差异有统计学意义(P0.05)。结论1飞秒激光制瓣预测性、重复性均好,制作出的角膜瓣均匀一致；2飞秒激光制瓣,术中引入的高阶像差小；3飞秒激光制瓣,术后对比敏感度优于板层刀组,术后视觉质量好。 【英文摘要】Background and Laser in situ keratomileusis is currently mainstream refractive surgery procedure.The first step of this surgery was made a corneal flap with microkeratome then excimer laser ablation the corneal stromal bed in correcting myopia and hyperopia and astigmatism.The advantage of this surgery was remained corneal epithelium and bowman’s membrane integrity. After operation visual acuity recover fast and less pain. The disadvantage of this surgery was used microkeratome. Many of the serious complications of laser assisted in situ keratomileusis are related to the use of the microkeratome. So creation of corneal flap is one of the most key procedure in LASIK which is also the most difficult part of the operation.The femtosecond laser is human currently in laboratory condition can obtain the shortest pulse. The femtosecond laser duration is very short, only a few femtosecond.Because cut corneal tissue safety and precised femtosecond laser widely use ophthemology field. Especially femtosecond laser made corneal flap in refractive surgery.This study was explore visual quality in LASIK using a femtosecond laser and microkeratome creat corneal flap.MethodsTwo hundred eyes of 100 cases were treated with laser in situ keratomileusis. The patients were devided into two groups.50patients with 100eyes created corneal flap by Ziemer femtosecond laser as the femtosecond group, another 50patients with 100eyes created corneal flap with a mechanical microkeratome as the microkeratome group. All eyes received wavefront-guided LASIK treatments performed with Technolas 217z100 excimer laser. Anterior segment optical coherence tomography was used to assess the thickness of corneal flap after 1month. The aberration and contrast sensitivity and visual acuity were analyzed 1week,1month,3month postoperatively respectively.Statistical analysis software SPSS16.0 was used to analyze the experimental data and clinical data.α=0.05 was used as a standard test.Results1 Corneal flap:Mean flap thickness in group femtosecond laser was 103.54±5.60(range88to131)μm. Mean flap thickness in group femtosecond laser was 102.17±4.80μm in right eyes and 104.42±4.97μm in left eyes. Mean flap thickness in group microkeratome was 130.30±14.03μm (range90to158)μm. Mean flap thickness in group microkeratome was 127.17±16.6μm in right eyes and 109.42±16.8μm in left eye.2 Aberration:The total high order aberrations and vertical comatic aberrations were significantly increased at postoperative in the microkeratome group, but not in the femtosecond group, there were statistical differences in each time point between two groups.(P<0.05). The postoperative spherical aberrations and horizontal comatic aberrations in two groups were higher than that before operation, and the increases of the microkeratome group were higher than that of the femtosecond group. 3 Contrast sensitivity:There were no statistically significant differeence for all spatial frequencies in photopic and photopic with glare condition postoperatively. In mesopic condition the contrast sensitivity improved at the spatial frequency(12.0、18.0cycles/degree) only in the femtosecond laser groups after 1 week.In mesopic with glare condition the contrast sensitivity all spatial frequencies have an improvement in femtosecond laser groups. However the contrast sensitivity in microkeratome group was decrease for all spatial frequencies 1 week postoperatively and restore to preoperative level 3 month.Conclusion1 Corneal flaps created with the femtosecond laser is extremely accurate and repeatability.2 Femtosecond laser shows induction of higher order aberrations to the microkeratome.3 The corneal flaps created with the femtosecond laser resulted in a faster recovery than mechanical microkeratome. 【关键词】角膜瓣 波前像差 对比敏感度 飞秒激光