  We introduce a class of null hypersurfaces of a semi-Riemannian manifold,
namely, screen quasi-conformal hypersurfaces, whose geometry may be studied
through the geometry of its screen distribution. In particular, this notion
allows us to extend some results of previous works to the case in which the
sectional curvature of the ambient space is different from zero. As
applications, we study umbilical, isoparametric and Einstein null hypersurfaces
in Lorentzian space forms and provide several classification results.
