  We present brief review of two probable physical mechanisms that can explain
the results of photometric and spectropolarimetric observations of magnetic
white dwarfs: vacuum polarization effect into a strong magnetic field and,
so-called, magnetic collision induced absorption (magnetic CIA). Both
mechanisms provide observed rotation of polarization ellipse and suppression of
spectral energy distributions. The results of spectropolarimetric observations
of magnetic white dwarfs made at Russian BTA-6m and the results of the near
infrared photometric observations with Russian-Italian AZT-24 telescope located
at Campo Imperatore are also presented.
