If you purchase vintage eyeglass frames from flea markets or individual sellers on eBay or etsy (or if you inherit a few pairs from an elderly aunt), there is a good chance that there will already be a pair of prescription lenses in them. Since your prescription will probably not match, you’re going to want to remove those lenses.
Of course, an optician will do it for you in the course of replacing the lenses with your own prescription, but you can also do it yourself. Here’s how.
1. Make sure you’re working over a soft surface. You don’t want the lens to shatter when it pops out.
2. Examine the frame. Is it metal or plastic? Are there screws holding the eye sockets together (most common in metal frames) or is it one unbroken mold (most common with plastic frames)? Be sure to look on the underside of the frame, near the temples, for screws that hold the rims together.
3. If there are screws, use an eyeglasses screwdriver to remove them. If you’re a glasses wearer, chances are you have one of these already. If not, many drugstores such as Walgreen’s carry them. Make sure you don’t force the screw, or you run the risk of stripping the threads so that it won’t hold firm in the socket again. For many frames, the lenses will pop right out after the screws have been removed.
4. If the frame is molded plastic without any visible screws holding in the lenses, you will have to heat the frame to make the plastic more pliable. Do this by submerging the frame in hot (NOT boiling) water for around a minute, or by pointing a hairdryer at it.
3. Once the plastic has been heated, hold the glasses and gently push down on the lens with your thumb. Don’t force it or you run the risk of breaking the frame. For some older pairs, the process is easier since the lenses have become loose over time.
I’d also like to point you to the Fifties Frames guide for removing lenses here:
http://fiftiesframes0.blogspot.com/2009/08/out-with-old-and-in-with-new.html