Berendschot T T, DeLint P J, van Norren D
Helmholtz Institute, Department of Ophthalmology, Utrecht University, Netherlands.
Invest Ophthalmol Vis Sci. 1996 Dec;37(13):2716-23.
To determine the origin of the tapetal-like reflex (TLR) in carriers of X-linked retinitis pigmentosa.
Spectral fundus reflectance of carriers of X-linked retinitis pigmentosa was measured and compared with that of normal subjects. The influence of visual pigment was determined by measuring the density difference, that is, the difference between the logarithmically scaled spectra of a bleached and a dark-adapted retina. In addition, fundus reflectance maps at 514 nm were made with a scanning laser ophthalmoscope in a bleached and a dark-adapted condition. Finally, the optical Stiles-Crawford effect was measured to determine the angular sensitivity of the TLR.
The tapetal-like reflex showed its spectral fingerprint in a high reflectance for wave-lengths smaller than 600 nm. The density difference measured at retinal sites of TLR was significantly larger than in normals, but the shape of the spectrum was similar. The optical Stiles-Crawford effect showed a similar peakedness for all retinal positions. However, in the TLR region, the amplitude of the directionally dependent part was increased dramatically. For the foveal region, no differences were observed.
An increase in reflectance of the outer segments of the photoreceptors in heterozygotes compared to normals can explain both the high-density difference and the large amplitude of the Stiles-Crawford effect. An earlier suggestion that only cones contribute to the TLR is unlikely.
确定X连锁视网膜色素变性携带者中毯样反射（TLR）的起源。
测量X连锁视网膜色素变性携带者的眼底光谱反射率，并与正常受试者进行比较。通过测量密度差来确定视色素的影响，即漂白视网膜和暗适应视网膜的对数标度光谱之间的差异。此外，使用扫描激光检眼镜在漂白和暗适应条件下制作514nm处的眼底反射率图。最后，测量光学斯泰尔斯-克劳福德效应以确定TLR的角度敏感性。
毯样反射在波长小于600nm时呈现高反射率的光谱特征。在TLR视网膜部位测量的密度差明显大于正常受试者，但光谱形状相似。光学斯泰尔斯-克劳福德效应在所有视网膜位置均呈现相似的峰值。然而，在TLR区域，方向依赖性部分的幅度显著增加。在黄斑区域未观察到差异。
与正常受试者相比，杂合子中光感受器外段反射率的增加可以解释高密度差和斯泰尔斯-克劳福德效应的大幅度。先前关于只有视锥细胞对TLR有贡献的观点不太可能成立。
