Mark Hornfeld, DO

It depends on your prescription. For mild to moderate myopia, PRK or LASIK are both reasonable options with a central corneal thickness of 540

Keratoconus is still a contraindication to PRK, and rightfully so. The risk of corneal ectasia is too high. this may change as new treatment modalities become available, namely collagen crosslinking. But as of this moment (July 2015), PRK for keratoconus is not a good idea.

With so many possible causes for the redness, you're best off going back to where you had the procedure done for a full evaluation.

PRK and ICL are both options, but you may want to consider having LASIK with a femtosecond-created flap. The femtosecond laser can create a thin flap which should fit your particular parameters. Remember that whichever option you choose, each procedure carries its own unique set of risk factors. Discuss with your ophthalmologist.

The "farsightedness" you've developed is called "presbyopia." It is the difference between your distance correction and your near correction. Now that you are in your forties, the glasses you need for the distance is different than the glasses you need for reading.