Why do you have a blurry vision in the first days after prk refractive surgery?

Healing. In prk, the skin covering the cornea is removed and allowed to regrow by itself. As the skin is regrowing, the vision will be blurry. After a few days, the skin is healed and the vision will improve. Vision after prk will continue to improve for several weeks.
Edema. There is always some degree of swelling of the tissues after the laser treatment for both prk and lasik. The body recognizes this as abnormal and will absorb this fluid re-establishing good vision.