I also had PRK after RK surgery, age 52. My RK surgery was also done nearly 20 years ago in both eyes. Target - distance vision.

5 months post-op distance vision poor. Near vision is 20/20. My vision has diurnal fluctuation over 1 diopter that occurs from morn-eve, measured by refraction specialist. Both corneas steepen symmetrically and become more myopic morn-eve. Morning refraction test used for PRK surgery. Distance vision deteriorates horribly from morn-eve because of diurnal shift. Chief complaint-initial visit was fluctuating vision. No multiple refraction tests done morn-eve pre-surgery. Expert comment on this?