The laser treatment for correct vision nowadays is using laser beam to burn off part of the cornea to make a curvature on the cornea. The created curvature works like a lens to replace eye glasses. Eye doctors know that the burned cornea could grow back to original shape in few days. They apply eye drops to prohibit the burned cornea from recovery. The created curvature will become permanent after a period of time with applying medication. The cornea has fast recovery quality.
Quite a while ago when I was working in Dobson research laboratory, a young engineer told me that when he was on queue of check in on airlines, somebody pushed him behind while he was holding his passport, the paper scratched his cornea.
When my daughter was still a small girl, she scratched her cornea on shuffling paper. I calm her that she could be healed in few days.
Not long ago, when I passed by a young tree on spring time, a branch went between my eye glasses had scratch my cornea. I instantly saw blurry on my right eye. Tears keep on pouring out from my eyes. I was very afraid even I understand it could be healed. My left eye, which has a lower vision then my right eye, has a better vision now.
My tears keep on poring out on second day. It was distracting to see bright things. I could see a halo on the edge of objects. It has same feeling of dilating eye drop on eye examination. My tears stopped on the third day. Then, I saw a double image on the injured eye. If there is a pole on far end, I could see two poles on my right eye. My vision improved after a few days, but the problem seemed to persist. I felt my scratch is on the centre of cornea, because I could see better in the dark. My vision was worse on bright sunny days. It is because of iris is close to smallest size on high intensity light. Under such condition, my vision is relying on the scratched portion of my cornea. I request an emergency eye examination with my eye doctor. My eye doctor did not express seriousness on my injury. He examined my cornea with optical equipment and said it was already healing. I seriously asked him if my double vision was a permanent damage. He said my cornea could be resurfaced in few weeks time. He advised me not to panic. He sent me home without giving any prescription.
After two weeks, my vision seemed improved a lot. But the trouble still exists on bright light. My left eye returned worse as before while my right vision improved. I was delighted. My vision is very near total recovery after a month. I expect it will be on complete recovery in few months time.
The human eye is a very precise and amazing optical organ. We could compare it to a camera. A scratch on camera lens causes permanent damage unless you dismantle the lens and send it to the factory for re-polishes. I have never seen a man-made camera which can polish its own lens. God made our eyes self-repairable. It is an amazing creation.