Hi moneyplant
To begin with, it is worth noting that TransPRK is technically the simplest possible laser refractive procedure, that any refractive surgeon can do. LASIK, on the other hand, requires skill and experience with the femtosecond laser (and in the past, the microkeratome) in order to safely create a good, uniform, well centered flap. In other words, any LASIK surgeon can also offer TransPRK, but it is not necessarily true the other way around.
Having said that, what are the pros and cons of each procedure?
TransPRK, like any other surface procedure (PRK, LASEK, epiLASIK) involves removal of the corneal epithelium thus resulting in a 'raw' surface afterwards. As such, there is usually some pain and tearing for the first 2 days. After this, the eye becomes comfortable again but vision becomes blurred, and this blurring can take anywhere from a few weeks to a few months to completely clear.
With LASIK, there is no 'raw' surface after surgery. As such, there is no pain afterwards and vision is very good from the next day onwards.
With TransPRK, although the corneal nerve endings are not cut, they are vapourised away by the excimer laser and also do take some time to regenerate. That is why there is also some amount of dryness after TransPRK. With LASIK, the corneal nerve endings are cut but usually regenerate into the flap within several months. That is why for most patients, dryness after LASIK is also a temporary issue only.
It is true that a LASIK flap does not stick back to the cornea with the original strength after surgery. There is a small chance of a freak accident, such as getting poked very hard in the eye by a sharp object at the flap edge, causing the flap to shift even a long time after the procedure. With any surface procedure (TransPRK, PRK, epiLASIK, LASEK), there is no flap, hence if the eye is poked afterwards, there is no flap to shift and the result is usually only a scratch.
However, if the treatment left some amount of spectacle power and an enhancement/adjustment becomes necessary, it is much better to have a flap. Doing a LASIK enhancement means clear vision the next day after enhancement, whereas for TransPRK/PRK/epiLASIK/LASEK, any enhancement must be a surface procedure again, thus needing another 2 days of pain and possibly several months of blurring before everything recovers again.
So to recap, in deciding between TransPRK (or any other surface procedure), and LASIK, consider the low likelihood that your cornea will get poked very hard, vs the certainty of pain and prolonged blurring with any surface procedure. Consider also, in the ~1% chance of needing an enhancement, would you prefer to see clearly the next day after enhancement or would you be happy to wait through a second period of pain and blurred vision for several months.
If after considering the above, you are very keen to have TransPRK (or any surface procedure such as PRK/epiLASIK/LASEK), just let your LASIK doctor (any LASIK doctor) know and he/she will be happy to oblige. In my experience, though, LASIK's benefits seem to outweigh it's cons for the majority of people, who desire the much more comfortable and quicker way to clear vision.
