屈光手术后干眼患者角膜共焦镜观察

【作者】 余晨颖；

【导师】 李莹；

【作者基本信息】 北京协和医学院 ， 临床医学， 2013， 博士

【摘要】 目的观察LASIK术后角膜中央基底层下上皮神经丛的再生,研究其数量及形态参数与干眼指标间的关系,以及神经再生及干眼程度与术后时间、不同术式、切削深度等指标之间的相关性,从而帮助我们更全面地了解LASIK术后干眼症的病理生理机制,以期优化其治疗方案。方法随机入选2011年10月至2012年9月在北京协和医院眼科行传统LASIK/飞秒LASIK手术的近视患者42例(84眼)。根据患者随访时间分为LASIK术后半年组19例(38眼)和LASIK术后一年组23例(46眼)。对患者进行的术后检查主要包括干眼相关检查和角膜共聚焦显微镜检查两部分,其中前者又可分为泪液三项试验和OSDI问卷调查,后者即采用HRT III共聚焦显微镜着重对基底层下上皮神经丛进行观察,在单眼的角膜中央区域内任意选择三点行立体扫描,从中挑选出基底层下上皮神经最丰富且最清晰的三幅图像后使用ACCMetrics软件对这些图像进行神经数量及形态参数的统计并取平均值,具体参数包括神经纤维主干及主干上分支的密度(CNFD和CNBD)、神经纤维长度(CNFL)、神经总分支节点的密度(CTBN)、以及神经纤维的宽度(CNFW)和弯曲度(CNFT)等。采用独立样本t检验的方法比较术后不同随访时间组(半年组、一年组)之间,以及不同种类LASIK术式组(传统组、飞秒组)之间神经参数与干眼指标的差异；此外,根据实际情况对神经参数与干眼指标,以及两者分别与切削深度及基质层厚度之间的关系行偏相关及双变量相关性分析。结果1.干眼指标,LASIK术后一年组患者的Schirmer试验值和TBUT值均显著大于半年组(t=-2.340,-5.403,P<0.05),荧光素染色分值显著小于半年组(t=2.634,P<0.05),但两组间的OSDI评分未见统计学显著性差异(t=1.207,P>0.05)。神经参数,LASIK术后一年组患者的CNFD、CNBD、CNFL、CTBN值均显著大于半年组(t=-3.293,-4.501,-7.091,-4.240, P<0.01),但是两组间的CNFW、CNFT值均未见显著性差异(t=1.480,0.474,P>0.05)。2. LASIK术后半年组,CNBD值与荧光素染色评分值呈负相关(r=-0.346,P<0.05),其余神经参数与干眼指标均无相关性(P值均>0.05)。LASIK术后一年组,CNFD值与Schirmer试验值呈正相关(r=0.321, P<0.05), CNBD、CTBN、CNFT值与Schirmer试验值呈负相关(r=-0.347,-0.340,-0.325,P<0.05),而CNFW值则与OSDI评分值呈正相关(r=0.342,P<0.05),其余神经参数与干眼指标均无相关性(P值均>0.05)。3.无论是LASIK术后半年组还是一年组,行传统LASIK手术的患者其各项干眼主客观指标和神经数量及形态参数与行飞秒LASIK手术的患者相比不存在任何显著性差异(P值均>0.05)。4. LASIK术后半年组,神经纤维的数量及形态参数以及干眼指标与手术切削深度及残留基质床厚度均无相关性(P值均>0.05)。LASIK术后一年组,TBUT值与手术切削深度呈负相关(r=-0.297,P<0.05),而其余神经参数及干眼指标与手术切削深度及残留基质床厚度均无相关性(P值均>0.05)。结论1. LASIK术后一年患者的干眼客观指标较术后半年患者显著改善,且其角膜中央基底层下上皮神经丛主干及分支的数量、神经纤维的长度均较术后半年患者显著增加。2. LASIK术后半年及一年患者角膜中央基底层下上皮神经丛的某些神经参数与干眼指标存在相关性,尤以术后一年者较为明显。3.传统LASIK与飞秒LASIK相比,其对术后半年及一年患者的干眼指标和神经参数所产生的影响无显著差异。4. LASIK术后一年患者的TBUT值与手术切削深度呈负相关。更多还原

【Abstract】 ObjectiveTo observe the regeneration of subbasal epithelial nerve plexus in central cornea after LASIK surgery, and study the correlation between its measurements and dry eye test values, so as to promote our knowledge about the pathophysiological mechanism of post-LASIK dry eye and optimize its therapeutic options.MethodsForty-two myopic patients (84eyes) who had conventional LASIK/femtosecond-assisted LASIK from October2011to September2012in PUMCH were included in this cross-sectional study. Patients were divided into two groups (six-month group and one-year group) based on the post-LASIK follow-up period. Subjective and objective dry eye tests were carried out to determine patients’ degree of post-LASIK dry eye, and confocal microscopy was used to observe the regeneration of subbasal epithelial nerve plexus that could then be analyzed by ACCMetrics software using quantitative parameters, such as the density, length, tortuosity and width of corneal nerve fiber. The quantitative data of the two groups was compared using an independent sample t test, and the correlation among dry eye test values, nerve fiber measurements, depth of excimer laser ablation and thickness of residual stromal bed was assessed by partial or bivariate correlation method.Results1. The values of Schirmer test and TBUT were higher and the score of fluorescein staining was lower in patients from the one-year group when compared with those from the six-month group (t=-2.340,-5.403,2.634, P<0.05), but there was no statistically significant difference in the OSDI score between the two groups (t=1.207, P>0.05). In terms of nerve fiber measurements, the values of CNFD, CNBD, CNFL and CTBN in patients from the one-year group were all higher than those from the six-month group (t=-3.293,-4.501,-7.091,-4.240, P<0.01), but there was no statistically significant difference in the values of CNFW and CNFT between the two groups (t=1.480,0.474, P>0.05).2. For patients in the six-month group, the value of CNBD was negatively correlated with the score of fluorescein staining (r=-0.346, P<0.05), while none of the other nerve fiber measurements was correlated with any of the dry eye test values (P>0.05). However, for patients in the one-year group, the value of Schirmer test was positively correlated with that of CNFD (r=0.321, P<0.05), but negatively correlated with that of CNBD, CTBN, and CNFT respectively (r=-0.347,-0.340,-0.325, P<0.05), and the value of CNFW was positively correlated with the score of OSDI (r=0.342, P<0.05), while none of the other nerve fiber measurements was correlated with any of the dry eye test values (P>0.05).3. There was no statistically significant difference in either dry eye test values or nerve fiber measurements between patients who had conventional LASIK surgery and those who had femtosecond-assisted LASIK surgery (P>0.05).4. For patients in the six-month group, none of their nerve fiber measurements or dry eye test values was correlated with either the depth of excimer laser ablation or the thickness of residual stromal bed (P>0.05). However, for patients in the one-year group, the value of TBUT was negatively correlated with the depth of excimer laser ablation (r=-0.297, P<0.05), while none of the other nerve fiber measurements or dry eye test values was correlated with either the depth of excimer laser ablation or the thickness of residual stromal bed (P>0.05). Conclusions1. For patients who are one-year post-LASIK, their values of objective dry eye testsare greatly improved, and the density and length of their subbasal epithelial nerve plexus in central cornea are significantly increased when compared with those of patients who are six-month post-LASIK.2. Some measurements of subbasal epithelial nerve plexus in central cornea arecorrelated with some of the dry eye test values, which are more common in one-year post-LASIK patients.3. The difference between conventional-LASIK and femtosecond-assisted LASIKdoes not significantly affect the dry eye test values and nerve fiber measurements in patients who are six-month or one-year post-LASIK.4. The TBUT value of one-year post-LASIK patients is negatively correlated withthe depth of excimer laser ablation.更多还原