  We investigate the role of relativistic and nonrelativistic optical
potentials used in the analysis of ($e,e'p$) data. We find that the
relativistic calculations produce smaller ($e,e'p$) cross sections even in the
case in which both relativistic and nonrelativistic optical potentials fit
equally well the elastic proton--nucleus scattering data. Compared to the
nonrelativistic impulse approximation, this effect is due to a depletion in the
nuclear interior of the relativistic nucleon current, which should be taken
into account in the nonrelativistic treatment by a proper redefinition of the
effective current operator.
