Greenfield David S, Knighton Robert W, Feuer William J, Schiffman Joyce C, Zangwill Linda, Weinreb Robert N
Department of Ophthalmology, University of Miami School of Medicine, Bascom Palmer Eye Institute, Florida 33418, USA.
Am J Ophthalmol. 2002 Jul;134(1):27-33. doi: 10.1016/s0002-9394(02)01512-x.
Corneal polarization axis (CPA) has been reported to affect retardation measurements obtained with scanning laser polarimetry (SLP). The purpose of this investigation was to prospectively determine whether correction for CPA improves the discriminating power of SLP for detection of mild-to-moderate glaucoma.
Cross-sectional analysis of normal and glaucomatous eyes.
We constructed a noninvasive slit-lamp-mounted device incorporating two crossed linear polarizers and an optical retarder to measure the slow axis of corneal polarization. Complete ocular examination, standard automated perimetry, SLP imaging, and CPA measurements were performed on normal and glaucomatous eyes. One eye/subject was enrolled; if both eyes of a patient were eligible for the study, the right eye was selected. For each of the 13 SLP parameters, logistic regression was used to determine if including CPA in the model influenced the ability to discriminate between normal and glaucomatous eyes.
Forty-three normal eyes (average visual field mean defect, -0.53 +/- 1.4 dB) and 33 glaucomatous eyes (average visual field mean defect, -5.93 +/- 6.5 dB) were enrolled. CPA was significantly correlated with summary retardation parameters (average thickness and integral values) in normal (r = 0.72-0.83, P <.001 for all values) and glaucomatous eyes (r = 0.43-0.62, P =.013 to <.001). Including CPA in the model improved the ability to discriminate between normal and glaucomatous eyes for five retardation parameters quantifying retinal nerve fiber layer (RNFL) thickness (range of P values: 0.045-0.001). For inferior average thickness, area under the receiver operating characteristic (ROC) curve increased significantly (P =.002) from 0.70 to 0.78 after accounting for CPA; with a sensitivity set at 80% specificity improved from 33% to 72%. Correlations between visual field corrected pattern standard deviation and average thickness, ellipse average, superior average, and inferior average significantly increased (range of P values,.018-.001) after adjustment for CPA (r = -0.35 and -0.45, -0.38 and -0.47, -0.46 and -0.57, and -0.42 and -0.49, respectively).
Correction for CPA significantly increases the correlation between retinal nerve fiber layer structural damage and visual function and significantly improves the discriminating power of SLP for detection of mild-to-moderate glaucoma.
据报道，角膜偏振轴（CPA）会影响通过扫描激光偏振仪（SLP）获得的延迟测量结果。本研究的目的是前瞻性地确定对CPA进行校正是否能提高SLP检测轻至中度青光眼的鉴别能力。
对正常眼和青光眼眼进行横断面分析。
我们构建了一种非侵入性的安装在裂隙灯上的装置，该装置包含两个交叉的线性偏振器和一个光学延迟器，用于测量角膜偏振的慢轴。对正常眼和青光眼眼进行了全面的眼部检查、标准自动视野检查、SLP成像和CPA测量。每例受试者入选一只眼；如果患者的双眼都符合研究条件，则选择右眼。对于13个SLP参数中的每一个，使用逻辑回归来确定将CPA纳入模型是否会影响区分正常眼和青光眼眼的能力。
纳入了43只正常眼（平均视野平均缺损，-0.53±1.4 dB）和33只青光眼眼（平均视野平均缺损，-5.93±6.5 dB）。在正常眼（r = 0.72 - 0.83，所有值P <.001）和青光眼眼（r = 0.43 - 0.62，P =.013至<.001）中，CPA与总结延迟参数（平均厚度和积分值）显著相关。将CPA纳入模型提高了对五个量化视网膜神经纤维层（RNFL）厚度的延迟参数区分正常眼和青光眼眼的能力（P值范围：0.045 - 0.001）。对于下方平均厚度，在考虑CPA后，接受者操作特征（ROC）曲线下面积从0.70显著增加到0.78（P =.002）；当敏感性设定为80%时，特异性从33%提高到72%。在对CPA进行调整后，视野校正模式标准差与平均厚度、椭圆平均值、上方平均值和下方平均值之间的相关性显著增加（P值范围，.018 -.001）（r分别为-0.35和-0.45、-0.38和-0.47、-0.46和-0.57以及-0.42和-0.49）。
对CPA进行校正显著增加了视网膜神经纤维层结构损伤与视觉功能之间的相关性，并显著提高了SLP检测轻至中度青光眼的鉴别能力。
