Han Meng, Giese Günter, Bille Josef
Opt Express. 2005 Jul 25;13(15):5791-7. doi: 10.1364/opex.13.005791.
Collagen, as the most abundant protein in the human body, determines the unique physiological and optical properties of the connective tissues including cornea and sclera. The ultrastructure of collagen, which conventionally can only be resolved by electron microscopy, now can be probed by optical second harmonic generation (SHG) imaging. SHG imaging revealed that corneal collagen fibrils are regularly packed as a polycrystalline lattice, accounting for the transparency of cornea. In contrast, scleral fibrils possess inhomogeneous, tubelike structures with thin hard shells, maintaining the high stiffness and elasticity of the sclera.
胶原蛋白作为人体中含量最丰富的蛋白质，决定了包括角膜和巩膜在内的结缔组织独特的生理和光学特性。胶原蛋白的超微结构传统上只能通过电子显微镜来分辨，现在可以通过光学二次谐波产生（SHG）成像进行探测。SHG成像显示，角膜胶原纤维以多晶格的形式规则排列，这是角膜透明的原因。相比之下，巩膜纤维具有不均匀的管状结构，外壳薄而坚硬，维持了巩膜的高硬度和弹性。
