  We present a new method to calculate optical properties of strongly
correlated systems. It is based on dynamical mean field theory and it uses as
an input realistic electronic structure obtained by local density functional
calculations. Numerically tractable equations for optical conductivity, which
show a correct non-interacting limit, are derived. Illustration of the method
is given by computing optical properties of the doped Mott insulator
La_{1-x}Sr_xTiO_3.
