The results of a photometric analysis of edge-on spiral galaxies in three blue fields of the Hubble Space Telescope (HDF-N, FDF-S, HUDF) are discussed. It is shown that galaxies at z ≈ 0.5 have lower values of the radial exponential scales h _r of the stellar disks compared to nearby galaxies. The observed variation in the scales of the disks is consistent with a n h _r ∝ (1 + z) ^–n law, where n ≈ 1. Indications are found of a significant reduction in the fraction of galaxies with B/PS bulges from z=0 to z=1.