I will soon become a 4th year PhD student of Theoretical Physics, Astronomy and Astrophysics at the Institute of Theoretical Physics in the Charles University, Prague, The Czech Republic. My background covers not only theoretical relativistic physics, but also plasma physics, since I obtained a master degree in both. Topic of my PhD thesis is focused on description of light rays propagating around compact gravitating objects (such as black holes, neutron stars) in refractive and dispersive media (plasma). Last academic year I spent at the Stanford University working with prof. R. Blandford on gravitational lensing with analyzing JWST data. During the rest of my PhD, I would like to find a more precise description of plasma used in my models to derive results allowing reasonable comparison with measurements.