We have studied the quantitative morphology and structural parameters of the bright galaxy population in the Nordic Optical Telescope (NOT) sample, which consists of five clusters of galaxies within the redshift range 0.18 ≤ z ≤ 0.25, imaged in the central 0.5-2 Mpc in very good seeing conditions. We have obtained that the structural parameters of E/S0 galaxies are similar to those showed by galaxies in low redshift clusters. However, the disc scales have a different behaviour. In particular, the scales of the discs of galaxies at medium redshift clusters are statistically different from those located in similar galaxies in the Coma cluster but, the scales of the discs of galaxies in medium redshift clusters are similar to nearby field galaxies. The results suggest that the evolution of the disc component of galaxies in clusters is faster than in field ones. This indicates that spiral galaxies in clusters have suffered a strong evolution in the last 2.5 Gyr. Mechanisms like galaxy harassment showing timescales of ˜ 1Gyr could be the responsible of this disc scale evolution.