Plasma rich in growth factors (PRGF-Endoret) represent a new technology using autologous proteins, growth factors and biomaterials as therapeutic formulations for different regenerative purposes. Under strict pharmaceutical development, it is possible to develop biologically stable eye drops, which have been shown to be useful for treating diverse ocular surface diseases. PRGF-Endoret eye drops could be an alternative therapy for patients with NK, and thus the objective of this clinical trial is to demonstrate its possible efficacy and its safety in patients with NK in stages 2 and 3.