  Elastic scattering angular distributions for systems with reduced mass
between 3 and 34 and energies varying between 25 and 120 MeV/nucleon were
analyzed. The stable $^4$He, its exotic partner $^6$He, and the weakly bound
$^{6,7}$Li nuclei were included as projectiles in the systematics. Optical
model data analyzes were performed with an adjustable factor of normalization
included in the imaginary part of the potential. These analyzes indicated a
reduction of absorption for systems with small reduced masses that was detected
due to the refractive nature of the scattering by light systems.
