频域OCT对正常人和青光眼光感受器细胞层厚度的检测

Photoreceptor layer thickness measurement in normal and glaucomatous eyes with spectral domain OCT

背景青光眼以视网膜内层的神经节细胞丢失为主要病理特征，但其是否累及视网膜外层尚有争议。部分研究认为青光眼将导致视网膜外层（光感受器）功能的异常，而病理学研究得出了不同的结论。目的用频域OCT测量正常人和青光眼患者光感受器细胞层的厚度，探讨青光眼对光感受器细胞层厚度的影响。方法采用病例对照研究。用频域OCT（SDOCT）对正常人38例38眼和青光眼患者48例48眼的黄斑区进行扫描，由一位检测者采用Sigma图像分析软件盲法测量黄斑中心凹和旁中心凹处（中心凹外1．5mm）视网膜光感受器层的厚度。同时采用时域OCT（Stratus OCT）测量所有检测眼的视盘周围视网膜神经纤维层（RNFL）厚度，比较正常组和青光眼组光感受器细胞核层的平均厚度，分析光感受器细胞层厚度与RNFL厚度的关系。结果正常组和青光眼组在黄斑中心凹光感受器细胞核层厚度分别是（96．7±10．7）μm、（103．7±13．3）μm，差异有统计学意义（P=0．011）；中心凹光感受器内节和外节层厚度分别是（59．3±5．5）μm、（59．5±5．5）μm，差异无统计学意义（P=0．890）。正常组和青光眼组在中心凹外3mm处光感受器细胞核层厚度分别是（70．9±14．0）μm、（68．7±10．7）μm，光感受器内节和外节层厚度分别为（45．2±6．4）μm，（43．6±5．5）μm，差异均无统计学意义（P=0．410，P=0．228）。黄斑中心凹处光感受器细胞核层厚度和RNFL厚度两者有二元线性关系（γ=-0．019X。＋2．73X＋10．34，R^2=0．211，P=0．005）。结论青光眼的黄斑中心凹光感受器细胞核层显著增厚，并随病程的变化而改变。

Background Glaucoma is primarily characterized by the damage of retinal ganglion cells in the inner layer. Whether the outer retinal layers are involved is controversial. Although the functional abnormality of the outer retinal layers have been determined, structural studies present different outcomes. Objective This study measured and compared photoreceptor layer thickness between normal and glaucomatous eyes using spectral domain optical coherence tomography（ OCT）. Methods A case-control study was designed. The macular area of 38 eyes from 38 normal volunteers and 48 primary open-angle glaucomatous eyes （POAG） were imaged by spectral domain OCT（ SD OCT）. The outer nuclear layer（ONL） and inner and outer segments（IS/OS） layer thicknesses in fovea and parafovea（ 1.5 mm from the fovea） were measured by a single masked observer using an image analysis software （ SigmaSean Pro version 5.0）. Retinal nerve fiber layer（RNFL） thicknesses of the 86 eyes were measured by Stratus OCT. The photoreceptor layer thieknesses between normal and glaucomatous eyes were compared. The eorrelation of photoreeeptor with RNFL thicknesses was evaluated with linear and non-linear regression models. Results The outer nuclear layer（ONL） thickness in the fovea in normal and glaucomatous eyes were 96.7_＋10.7 μm and 103.7-＋ 13.3 μm, respectively, with a significant difference （ P = 0. 011 ）. The inner and outer segments （IS/OS） layer thicknesses in the fovea in the two groups were 59.3±5.5 μm and 59.5±5.5 μm, respectively, without significant difference（ P=0. 890）. The outer nuclear layer（ONL） thicknesses in the parafovea in normal and glaucomatous eyes were 70.9±14.0 μm and 68.7±10.7 μm, respectively, （ P = 0. 410 ）. The inner and outer segments （ 1S/OS ） layer thicknesses in the parafovea in the two groups were 45.2±6.4 p.m and 43.6±5.5 μm, respectively（ P = 0. 228 ）. The relationship between ONL and RNFL thickness was best described with a second order polynomial regression modelassociation（Y=-0. 019X2＋2.73X＋10. 34,R2=0. 211,P=0. 005） . Conclusion The foveal ONL thiekness is inereased in glaucomatous eyes. The alteration of foveal ONL thickness is associated with the severity of the disease.