Figure 3.

Comparison of transparent and opaque human lenses by electron microscopy and SAXS.A, electron micrographs of cells in a transparent and opaque human lens demonstrate that very small changes in SRO can reduce transparency. Very small differences in SRO between the opaque and transparent lens cell cytoplasm may not be obvious. Quantitative analysis is necessary to determine which cells contain transparent SRO, where destructive interference of scattered light permits transparency, despite the highly concentrated proteins (51). B, SAXS from fresh samples of opaque and transparent lens cytoplasm confirms the observations by electron microscopy (A). The plots are nearly identical except for a small increase in large scattering components in opaque cytoplasm (dashed line). The result demonstrates the impact that very small differences in cytoplasmic SRO can have on lens transparency and can be a model for the earliest reversible stages of formation of pathological cataract. “s” is size; “A” is angstroms; and “I” is intensity (50). SAXS, small-angle X-ray scattering; SRO, short-range order.