Mellem-Kairala Mariane B, Elsner Ann E, Weber Anke, Simmons Ruthanne B, Burns Stephen A
Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.
Invest Ophthalmol Vis Sci. 2005 Mar;46(3):1099-106. doi: 10.1167/iovs.04-0574.
To improve detection and quantification of peripapillary hyperpigmentation, associated with aging, open-angle glaucoma, and age-related macular degeneration.
A computational approach was implemented with a readily available polarimeter used in glaucoma diagnosis, a nerve fiber analyzer (GDx; Laser Diagnostic Technologies, San Diego, CA). Using near-infrared illumination at each of 20 input polarizations, a series of image pairs was digitized. One image is made from the light returning from the eye that is polarized parallel to the input light, and the other image is made from the light that is rotated by 90 degrees from the input polarization. Using raw data from these 40 images, and a simplified model of ocular polarization properties, images were computed based on their polarization content. Regions of hyperpigmentation, selected using stereo color fundus photographs, were quantified in three types of polarimetry images: (1) a depolarized light image resulting mainly from multiply scattered light; (2) an average image that is typical of confocal images; and (3) a birefringence image. Measurements on versus off hyperpigmentation were made in nine persons with suspected glaucoma or patients with primary open-angle glaucoma, selected to have clinically visible hyperpigmentation.
In the depolarized light images, hyperpigmented regions were significantly brighter than comparison areas (P < 0.0425)-that is, had more scattered light and therefore more contrast (P < 0.037) than did color or other polarimetric images.
With this polarimetry imaging method, subretinal tissues such as those with hyperpigmentation can be visualized with increased contrast.
改善与衰老、开角型青光眼及年龄相关性黄斑变性相关的视乳头周围色素沉着的检测与定量分析。
采用一种计算方法，利用青光眼诊断中常用的一种现成的偏振仪——神经纤维分析仪（GDx；激光诊断技术公司，加利福尼亚州圣地亚哥）。在20种输入偏振状态下的每一种状态下使用近红外照明，将一系列图像对进行数字化处理。一幅图像由与输入光平行偏振的从眼睛返回的光形成，另一幅图像由与输入偏振旋转90度的光形成。利用来自这40幅图像的原始数据以及简化的眼偏振特性模型，根据其偏振含量计算图像。使用立体彩色眼底照片选择色素沉着区域，在三种类型的偏振测量图像中对其进行定量分析：（1）主要由多次散射光产生的去偏振光图像；（2）共焦图像典型的平均图像；（3）双折射图像。对9名疑似青光眼患者或原发性开角型青光眼患者进行色素沉着开与关的测量，这些患者被选择为具有临床可见的色素沉着。
在去偏振光图像中，色素沉着区域比对照区域明显更亮（P < 0.0425）——也就是说，与彩色或其他偏振测量图像相比，具有更多的散射光，因此对比度更高（P < 0.037）。
通过这种偏振测量成像方法，可以更清晰地显示视网膜下组织，如色素沉着组织。
