Аннотация:Measurements of dehydrated cornea and biological fluids are carried out in the THz frequency range. The measured data is used for the modeling of the cornea tissue. It is shown that the maximal sensitivity of diagnostic system to the cornea hydration value appears in frequency range less than 100 GHz. Since the optimal frequency is also depends on spectral parameters of THz setup we proposed using THz reflectometer based on difference frequency generation of a pair of continuous semiconductor lasers allowing fine tune of the frequency.