Depends on the fields rules. Lowest grade protection accepted anywhere would be full wrap around, single piece glasses (as in no snap on side shields, and the lenses AND frames must be ANSI rated. Other places may require ballistic lenses and a retention strap, while others require full seal ballistic and/or paintball goggles.
If your local field only requires glasses, let me give you some advice. Ensure your frames are rated as well, not just the lenses. Once your glasses are on there should be ZERO angles for a direct hit to the eye. If your lenses do not have the flares or wings that wrap right around the eye, then the are inadequate, period, end of discussion. A slash strap or retention strap is also a boon as glasses can fall off of your head.
Looking at the det cords, they are not designed for this kind of use. You could wear them shooting, but there is no wrap around protection for the sides of your eyes. In very rare circumstances people have gotten away with certain frames due to facial shape. Your going to be looking into something more like the Oakley SI M-frames. Full eye coverage by ballistic or safety lenses are minimum. Det cords will only protect from straight on.
Another piece of advice; safety glass or ANSI rated glasses are only designed and rated for one hit or strike. Once a BB has hit them, they are technically no good anymore. In order to have a 'full seal', then they must have a proper foam or rubberized gasket to seal around the eye. The lenses and frames do not count.
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