I (25yo) am interested in prk. mom had lasik done, but my little bro has keratoconus. my doc has never indicated i have kera. is prk safe for me?

PRK: http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3085147/ is the best site to understand the complex genetic-environmental interaction so no one can know exactly but at 25 i would go ahead with it if the eye doctor agrees.

PRK or LASIK : Regardless of your family history, at 25 years of age your eye doctor should be able to determine what risk (if any) you have for laser vision correction. During your vision correction evaluation, the doctors will be looking specifically for conditions that would make the procedure unsafe. Kerratoconus tops the list of conditions lasik surgeons are searching for.

Groden point strike: I use a corneal ectasia risk assesment system called the "groden point strike" system. You or your doctor can google the criteria. There is a good study that supports the sensitivity and specificity of this screening based on corneal topography and other factors. This system has a preference for prk over lasik. No system is foolproof and even this system fails to identify potential keratoconus.