PRK - Risks

Various professional associations such as the BVA (Professional Association of Eye Specialists) or the DOG (German Ophthamological Society) have classified PRK for the correction of eyesight flaws of up to -6 dpt as safe and reliable. ¹²

However, the operation is linked to risks. Corneal under- and over-corrections occur in rare cases. Such abnormalities can be handled about three months after the operation. Normally, the corneal lobule and the epithelial layer can be re-opened and the correction can be performed via PRK.
Consequences can be reduction in twilight and nighttime visibility (due to limited contrast sensitivity), the emergence of glare effects, and ring-shaped "light halos" (so-called halogons).¹³
Even serious complications - bleeding and infections - cannot be ruled out completely, but are extremely rare. Cicatrisation of the cornea rarely occurs.

Your doctor will be happy to explain any further risks as well as your personal risk situation.

Sources:
¹ DocWiki
^{2, 3, 5, 6, 11} Eye Clinic of Neumarkt, Cologne 
^{4, 8} German Professional Association of Eye Specialists e.V.
^{7, 9, 10, 12, 13} Commission for Refractive Surgery (KRC)