This paper reviews the results of studies of the photorefraction pheno
menon carried out by the author or with his direct participation at th
e S. I. Vavilov State Optical Institute over twenty-five years. The fe
atures of photoinduced anisotropy in photorefractive crystals belongin
g to various symmetry point groups are considered. The conditions for
optimizing the display of the photorefractive effect and for using it
to record images are presented. It is emphasized that local photoinduc
ed anisotropy is related to the spatial structure of the fields of the
volume photocharges in a crystal by complex nonlinear dependences who
se form is determined by the crystal symmetry.