  We derive the light deflection caused by the screw dislocation in space-time.
Space-time is medium which can be deformed in such a way that its deformation
is equivalent to the existence of metric which is equivalent to gravity. The
existence of the screw dislocations in cosmology is hypothetically confirmed by
observation of light bursts which can be interpreted as the annihilation of the
giant screw dislocations with antidislocations. The origin of the gravitational
bursts are analogical as the optical ones. They can be probably detected by
LIGO, VIRGO, GEO, TAMA and so on. The dislocation theory of elementary
particles is discussed.
