Yes. When you go outside, you should wear sunglasses to protect your eyes from damaging by some harmful rays.Since you have done PRK for a year, there is no need to wear prescription sunglasses, so just choose non prescription sunglasses which can block the UV rays and other harmful rays.
Yes,you need to wear sunglasses to protect your eyes from the UV lights,but you don't need to wear them for a full year as your eyes have completely recovered then.But anyway it is better to wear sunglasses outdoors.
Yes, you should protect your eyes from the UV lights and radiations outdoors bu wearing sunglasses. But it is not that necessary for you to wear prescription eyeglasses when indoors since you have done the PRK for a full year.