Welcome "aboard" of nearsighted. A light vision correct shouldn't be a big problem, however, as a person with -9 vision I could share some experience:
1) A regular optometrist have no f...n idea of shooting glasses and things they say are mostly total, complete BS. Considering price of glasses it is better to educate yourself a little bit to make informed decision.
2) "Prescription shooting glasses" is still prescription glasses yet:
a) where frame is big enough and strong enough to protect eyes. The key here is compliance with safety glasses standards such as Z87.1. Unfortunately, the optics almost never carry such frames in stock, so the task is to:
- find the frame yourself
- find optics who will take your frame (few of them do)
While where is a lot of safety glasses around, few of them works as prescription because of geometry of frame. Say anything "wrap-around" style cannot be made prescription without unacceptable level of distortion in the field of vision. The best of all I was able to find by the moment are canadian ArmoRX frame, especially 700X series with side shields works perfectly both for shooting and machining.
b) Now lenses. Of all options they offer, it's only thick impact resistant polycarbonate that makes safety glasses. That's important to know. They'd love to sell thin/high index lenses which are more expensive but... less strong.
3) Local optics yet to work best especially for multi-vision glasses. Any online optics makes kind of "average" glasses without proper alignment of the center of vision with eyes pupil. It may work but may not. Also, it is way easier to have glasses remade in local optics and this happens way more often than anyone wishes.
Progressive/single vision highly depends on use. If you do solely shooting, single vision will work much better, especially for precision shooting. Just make sure that the lenses are big enough so you don't have high level of distortion on peripheral vision.
I have to make progressive on mine, because of machining and safety officer duties, where I have constantly switch between reading/doing things.