National Synchrotron Light Source Symposium

Vision systems of mammals are susceptible to a variety of diseases related to alterations in the optical properties of the tissues responsible for handling the visible light inside the eye. Understanding the causes at molecular level is necessary for prevention or correction vision loss at early stages of the diseases, which has motivated several researches during last decades. Light and electron microscopy are among the most used tools in such researches, but they have some intrinsic limitations regarding either low resolution for probing tiny optically active features or small sampling areas with respect to the extension of the eye tissues. Here we shown that both limitations are overcome by employing an X-ray imaging technique where distinct radiation-tissue interaction processes are discriminated by the image detection system. The potential of this technique for application in ophthalmology is also demonstrated here by studying one of the most important eye diseases, the cataract. Two mechanisms leading to eye lens opacification are diagnosed: fiber cell compaction and distributions of protein aggregates. The latter was an unknown fact and it provides evidence that partial cataract can be related to small amounts of calcificated tissues, opening new opportunities for preventive or corrective treatments. Moreover, classification schemes for this ophthalmic disease can be elaborated based on density fluctuation maps of entire lenses.