Study Of Molecule Variation In Various Grades Of Human Nuclear Cataracts By Confocal Micro-Raman Spectroscopy

Confocal micro-Raman spectroscopy is employed to characterize various grades of human cataracts. Results show that the intensity ratio of the tyrosine doublet (I-855/I-833) changes from 1:1.07 +/- 0.03 to 1:1.17 +/- 0.05 with the aggravation of cataracts, which indicates that there are more tyrosine residues bound to strong H acceptors instead of bounding to water. The decrease of relative intensity at 880 cm(-1) band suggests that the "buried" tryptophan residues become "exposed" during the course of lens opacification. A three-dimensional principal component analysis is used to classify the Raman spectra of opacity tissues, which show a one-to-one correspondence with different grades of cataracts. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4762838]