  The Skyrmion number of paraxial optical Skyrmions can be defined solely via
their polarization singularities and associated winding numbers, using a
mathematical derivation that exploits Stokes's theorem. It is demonstrated that
this definition provides a robust way to extract the Skyrmion number from
experimental data, as illustrated for a variety of optical (N\'eel-type)
Skyrmions and bimerons, and their corresponding lattices. This method generates
not only an increase in accuracy, but also provides an intuitive geometrical
approach to understanding the topology of such quasi-particles of light, and
their robustness against smooth transformations.
