  We calculate the two-loop QCD corrections to paracharmonium decays $eta_{c}
rightarrow gamma gamma$ and $eta_{c} rightarrow g g$ involving light-by-light
scattering diagrams with light quark loops. Artificial large mass expansion and
convergence improvement techniques are used to evaluate these corrections. The
obtained corrections to the decays $eta_{c} rightarrow gamma gamma$ and
$eta_{c} rightarrow g g$ account for $-1.25 %$ and $ -0.73 %$ of the leading
order contribution, respectively.
