Cideciyan A V, Jacobson S G
Department of Ophthalmology, University of Miami School of Medicine, Bascom Palmer Eye Institute, FL 33136.
Invest Ophthalmol Vis Sci. 1994 Oct;35(11):3812-24.
To increase understanding of the tapetal-like reflex (TLR), a unique retinal feature in carriers of X-linked retinitis pigmentosa (XLRP).
Color fundus photographs of XLRP carriers were digitized at high resolution. A mathematical model of the imaging system was used to restore the digital retinal images. TLR was separated from the retinal background with an automated segmentation method. Mathematical morphology was used to estimate directional properties. Images from serial photos were registered and compared to study temporal progression.
Quantitative analysis of well-focused funduscopic images show point-like unit reflexes forming the TLR. The average unit reflex is circularly symmetric with a diameter of approximately 8.5 microns and has a maximum reflectance 40% higher than that of the neighboring nonreflex retina. Two or more unit reflexes form small elongate patches that can cluster together into larger patches. Both smaller and larger patches have a strong preferential direction toward the fovea. Comparison of images taken 23 years apart in one patient and 3 years apart in another patient show no detectable changes in the size and location of the reflexes.
The pattern of reflexes at high and low resolution suggests that the TLR represents an X-inactivation mosaic. Based on the size of the unit reflexes, the authors speculate that the cone photoreceptors participate in the TLR. The stability of the reflex over more than two decades questions the longstanding assumption that the TLR is a stage of the retinal degeneration.
加深对绒毡样反射（TLR）的理解，这是X连锁视网膜色素变性（XLRP）携带者独特的视网膜特征。
对XLRP携带者的彩色眼底照片进行高分辨率数字化处理。使用成像系统的数学模型来恢复数字视网膜图像。采用自动分割方法将TLR与视网膜背景分离。运用数学形态学估计方向特性。对连续照片的图像进行配准和比较，以研究其时间进程。
对焦良好的眼底图像定量分析显示，点状单位反射形成了TLR。平均单位反射呈圆形对称，直径约为8.5微米，其最大反射率比相邻的非反射视网膜高40%。两个或更多单位反射形成小的细长斑块，这些斑块可聚集在一起形成更大的斑块。较小和较大的斑块都强烈倾向于朝向中央凹。对一名患者相隔23年以及另一名患者相隔3年拍摄的图像进行比较，结果显示反射的大小和位置没有可检测到的变化。
高低分辨率下的反射模式表明TLR代表一种X染色体失活镶嵌现象。基于单位反射的大小，作者推测视锥光感受器参与了TLR。反射在二十多年间的稳定性对长期以来认为TLR是视网膜变性一个阶段的假设提出了质疑。
