Methods for early diagnosis of amyloid-related disorders based on the analysis of Raman spectra obtained from measurements carried out on body tissue (preferably on the eye lens) and spectral analyzers configured to carry out such methods.The diagnosis is made by detection of a signature of amyloid beta in the spectral range of 1500-1800 cm-1. An intensity ratio is calculated and the presence or absence of amyloid beta is determined based on said ratio. The intensity ratio may either be the intensity ratio of a C-H band and an amide I band, or the intensity ratio of different waveform components of the amide I band, in which case the component decomposition is obtained curve fitting.
