  The number of strong lens systems is expected to increase significantly in
ongoing and upcoming surveys. With an increase in the total number of such
systems we expect to discover many configurations that correspond to unstable
caustics. In such cases, the instability can be used to our advantage for
constraining the lens model. We have implemented algorithms for detection of
different types of singularities in gravitational lensing. We test our approach
on a variety of lens models and then go on to apply it to the inferred mass
distribution for Abell 697 as an example application. We propose to represent
lenses using A3-lines and singular points (A4 and D4) in the image plane. We
propose this as a compact representation of complex lens systems that can
capture all the details in a single snapshot.
