频域OCT视盘形态及神经纤维层厚度参数在青光眼诊断中的作用μ

背景青光眼是一种可引起视神经结构改变，继而导致不可逆视功能损害的一类疾病。光学相干断层扫描（OCT）通过对视盘形态以及神经纤维层的检测，有助于青光眼的早期诊断。目的探讨频域OCT视盘形态及神经纤维层厚度各参数在青光眼诊断中的作用。方法非干预性、横断面研究。应用频域RTVue OCT测量62例正常人和67例青光眼患者的视盘参数，以及视网膜各区域的神经纤维层厚度。用受试者工作特性曲线下面积（ROC）评价OCT每个检测参数区分正常眼与青光眼的能力大小。结果各型青光眼组患者的年龄明显大于正常组，各型青光眼组视野平均缺损（MD）和视野模式标准化差（PSD）值均明显大于正常组，差异均有统计学意义（P〈0．01）。正常组、青光眼组、开角型青光眼组和闭角型青光眼组间视盘面积的总体差异均无统计学意义（P=0．101、0．741、0．652）；正常人平均视网膜神经纤维层厚度为（109．758±9．095）μm，青光眼患者为（79．539±18．986）μm，明显低于正常人（P〈0．01）。在视盘周围8个神经纤维层区域中，正常人最厚的区域在颞下方和颞上方，分别为（150．109±18．007）μm和（146．105±15．529）μm，而青光眼患者最厚处在颞上方和颞下方，分别为（104．354±27．641）μm和（102．436±32．243）μm，但均较正常参数减小。正常人和青光眼患者鼻侧和颞侧视网膜神经纤维层厚度均较薄。视盘参数中，各型青光眼诊断效能最高的是盘沿容积和垂直杯盘比，二者的ROC值在总青光眼患者中分别为0．850和0．840，其特异性在80％时的敏感性分别为73．1％和76．1％，在开角型青光眼患者中分别为0．841和0．849，其特异性在80％时的敏感性分别为73．0％和81．1％，在闭角型青光眼患者中分别为0．862和0．830，其特异性在80％时的敏感性分别为73．3％和70．O％。视网膜神经纤维层厚度各参数中，诊断效能最高的是平均神经纤维层厚度，其ROC值在总青光眼、开角型青光眼、闭角型青光眼中分别为0．925、0．910和0．942，其特异性在80％时的敏感性分别为89．6％、89．2％和90．0％。视盘周围8个神经纤维层区域中，诊断效能最高的是IT区域，诊断效能最低的是TU和TL区域。结论RTVueOCT具有很好地区别正常人和青光眼患者的能力，在青光眼诊断方面是一个较实用的工具。

Effects of optic disc topography and retinal nerve fiber layer thickness measurement by spectral-domain OCT on diagnosis of glaucoma

Background Glaucoma is an optic neuropathy caused by structural damage of the optic nerve,and its early diagnosis is critical for arresting the irreversible damage of visual function. Optical coherence tomography (OCT) allows an early diagnosis of glaucoma by the measurements of the optic disc and retinal nerve fiber parameters. Objective This study was carried out to evaluate the effects of optic disc tomography and the measurement of the retinal nerve fiber layer (RNFL) thickness by spectral-domain OCT on the diagnosis of glaucomatous eye. Methods It was a noninterventional, cross-sectional study. The optic disc topographic parameters and total and regional RNFL thickness were measured by RTVue OCT in 62 normal eyes and 67 glaucomatous eyes. The area under the receiver operating characteristic curve( ROC ) was used to assess the ability to differentiate glaucoma eyes from normal eyes of each testing parameter. This trial complied with the Helsinki Declaration and was approved by the Clinical Trial Ethic Committee of Beijing Tongren Hospital. All of the participants signed the written informed consent before any medical examination. Results In the comparison of demography ,the ages of patients, the mean deficiency( MD ) and pattern standard difference( PSD ) of perimetry were obviously larger in the glaucoma group, primary open angle glaucoma ( POAG ) group and primary closure-angle glaucoma(PACG) group than those of normal controls( P＜0. 01 ). No significant differences were found in the disc area between a total glaucoma group, POAG group or PACG group and normal group ( P =0. 101,0. 741 and 0. 652, respectively) ;however, the average RNFL thickness between normal eyes and glaucomatous eyes were significantly different( 109. 758 μm versus 79. 539 μm, P＜0. 01 ). Among the eight regions around the optic disc, the thickest RNFL located at the inferotemporal( 150. 109 μm) and superotemporal( 146. 105 μm) regions in normal eyes,and at the superotemporal( 104. 354 μm) and inferotemporal( 102. 436 μm) regions in glaucomatous eyes. Both in normal and glaucomatous eyes,the thinnest RNFL located at the nasal(NU+NL) and temporal(TU + TL) regions. For optic disc topographic parameters,the highest ROC were observed in rim volume( ROC--0. 850,0. 841 and 0. 862 in total glaucoma,POAG and PACG, respectively) and vertical cup/disc ratio( ROC =0. 840,0. 849 and 0. 830 in total glaucoma,POAG and PACG,respectively), and the sensitivities for specificity cutoff set at 80％ were 73.1％ and 76. 1％ in total glaucoma,73.0％ and 81.1％ in POAG and 73.3％ and 70.0％ in PACG, respectively. For RNFL thickness ,the highest ROC was observed in average RNFL( ROC =0. 925,0. 910 and 0. 942 in total glaucoma, POAG and PACG,respectively) ,and the sensitivities for specificity cutoff set at 80％ were 89. 6％ ,89.2％ and 90. 0％ in total glaucoma,POAG and PACG, respectively. Among the eight regions around the optic disc, RNFL thickness of region IT achieved the highest ROC, RNFL thickness of region TU and TL had the lowest ROC. Conclusions RTVue OCT appears to be of fair discriminating ability in distinguishing normal from glaucomatous eyes. RTVue OCT shows promise for the diagnosis of glaucoma.