  We investigate the effects of gluon number fluctuations on the total
$\gamma\gamma$, $\gamma^*\gamma^*$ cross sections and the photon structure
function $F_2^\gamma(x,Q^2)$. Considering a model which relates the
dipole-dipole and dipole-hadron scattering amplitudes, we estimate these
observables by using event-by-event and physical amplitudes. We demonstrate
that both analyses are able to describe the LEP data, but predict different
behaviours for the observables at high energies, with the gluon fluctuations
effects decreasing the cross sections. We conclude that the study of $\gamma
\gamma$ interactions can be useful to constrain the QCD dynamics.
