  Microlensing by the stellar population of lensing galaxies provides an
important opportunity to spatially resolve the accretion disc structure in
strongly lensed quasars. Disc sizes estimated this way are on average larger
than the predictions of the standard Shakura-Sunyaev accretion disk model.
Analysing the observational data on microlensing variability allows to suggest
that some fraction of lensed quasars (primarily, smaller-mass objects) are
accreting in super-Eddington regime. Super-Eddington accretion leads to
formation of an optically-thick envelope scattering the radiation formed in the
disc. This makes the apparent disc size larger and practically independent of
wavelength. In the framework of our model, it is possible to make
self-consistent estimates of mass accretion rates and black hole masses for the
cases when both amplification-corrected fluxes and radii are available.
