频域光学相干断层扫描在视网膜神经纤维层厚度测量中的应用

Measurement of retinal nerve fiber layer thickness with spectral domain optical coherence tomography

目的应用频域光学相干断层扫描(OCT)测量非青光眼受试者和青光眼患者的视盘周视网膜神经纤维层(RNFL)厚度,并对测量结果进行重复性检验。方法非青光眼受试者和青光眼患者各30例纳入研究,随机选取受试者一侧眼的数据进行统计分析。应用Spectralis OCT对每位受试者进行视盘周RNFL厚度测量,应用"随诊"模式进行3次扫描。计算出受试者内部标准差(Sw)、变异系数(CV)和同类相关系数(ICC),以评价该仪器测量的可重复性。应用Spearman秩相关系数分析评估每位受试者RNFL厚度平均数值与其3次测量的标准差之间的关系。结果非青光眼受试者的CV数值范围为1.44%(全周厚度平均值)～2.58%(颞侧象限),青光眼患者的CV为1.73%(全周)～3.24%(颞侧象限);非青光眼受试者的ICC数值范围为0.977(颞侧象限)～0.990(鼻下45°扇形区),青光眼患者的ICC数值范围为0.981(颞侧象限)～0.997(下方象限);非青光眼受试者的Sw为1.33μm(全周)～2.36μm(颞上45°扇形区),青光眼患者的Sw为1.13μm(全周)～2.26μm(鼻上45°扇形区);RNFL厚度数值与测量变异性间无明显相关性(P>0.05)。结论高速扫描和眼跟踪系统使Spectralis OCT在测量非青光眼受试者和青光眼患者的视盘周RNFL厚度均有良好的可重复性,是青光眼长期随诊中对于其结构性损害可信赖的影像学检查技术。

Background The evaluation of optic nerve head and retinal nerve fiber layer （RNFL） thickness is essential in diagnosis and follow-up of glaucoma. Optical coherence tomography （OCT） is one of the imaging techniques for glaucoma,and the new developed technique of spectral domain OCT with faster scan speed is expected to reduce RNFL measurement variability. Objective The present study tried to evaluate the reproducibility of measurement method for determining peri-papillary retinal nerve fiber layer （RNFL） thickness with Spectralis spectral domain optical coherence tomography （SD-OCT）. Methods SDOCT was used in the lateral eyes of 30 non-glaucoma subjects and 30 glaucoma patients for the measurement of peri-papillary RNFL thickness. The measurement of peri-papillary RNFL thickness was repeated for three times during the same operation using the follow-up function of Spectralis OCT. The reproducibility was evaluated based on the within-subject standard deviation （Sw） , coefficient of variation （CV） and intraclass correlation coefficient （ICC）. Spearman＇ s rank correlation coefficient analysis was used to assess the correlation of the standard deviation of RNFL thickness values obtained from 3 times of measuring values in each participant. Results The CVs ranged from 1.44% （360° retina） to 2.58% （temporal quadrant） in non-glaucomatous eye and from 1.73% （360° retina） to 3.24% （temporal quadrant） in glaucomatous eyes. The range of ICCs was from 0. 977 of temporal quadrant to 0. 990 of inferior-nasal sector in non-glaucomatous eyes and from 0. 981 of temporal quadrant to 0. 997 of inferior quadrant in glaucomatous eyes. The Sw value showed a range from 1.33 μm of 360° retina to 2.36 μm of superior- temporal sector in non-glaucomatous eyes and from 1. 13 μm of 360° retina to 2.26 μm of superior-nasal sector in glaucomatous eyes. No significant correlations were found between RNFL thickness values and measurement variability for each participant （ P 〉 0.05 ）. Conclusion The fast scan speed and the tracking system allow an excellent reproducibility of Spectralis OCT in measuring peri-papillary RNFL thickness in both non-glaucoma subjects and glaucoma patients, indicating that SD-OCT is a reliable imaging technique for the evaluation of glaucomatous damage in a long-term follow up duration