I will address the effects of bar-driven secular evolution in discs by comparing their properties in a sample of nearly 700 barred and unbarred massive galaxies. Through detailed structural decompositions I will show that, as a population, barred discs tend to have fainter central surface brightness and larger disc scale lengths than those of unbarred galaxies. Bars rarely occur in high-surface brightness discs and tend to reside in moderately blue discs. These results show that bars induce noticeable evolution in the structural properties of galaxy discs, in qualitative agreement with longstanding theoretical expectations.