The insert is too small full lenses work best. Contact DR Frank Rively for prescription Ranger Lenses. He does the best job.... Frank makes/grinds the shapes for all ranger frames new and old. He is also a Ranger Distributer.
You can contact him by calling or better texting him @ 570 313 7176
I used them for several years, before my recent cataract surgery.
I bought mine through Texas Shooters Optical, and had great experience with my purchase. I opted to use single vision lenses instead of multifocal, since they'd be used exclusively for shooting.
The inserts are helpful, and reduce the price of shooting glasses, since the XLW lenses are interchangeable, and you only need to replace the insert lenses.
The inserts sit very close to your eyes; much closer than standard glasses. Until you get used to the closer lenses, it is a bit uncomfortable. After the initial discomfort, the inserts became less noticeable, but they're always "there".
The inserts tend to fog up more, and take longer to clear in cold weather; or if it's extremely warm and humid. There just isn't enough air flow behind the lenses to keep them from fogging. I've used several different defogging compounds, with not a great deal of success.
The base eight curve of the XLW is great, but there's just no way of grinding a lens in that design.
I look at the XLW's, with the inserts, as a more complicated way to accomplish what can be done with "standard" shooting glasses (Decot, Ranger XL, etc.). That's no knock on Randolph Engineering, but just the facts of the design.
Since my cataract surgery, I have no need for prescription glasses (with the exception of "cheaters"). I love the XLW's without the inserts, and I picked up a set of XL's from my son, who now wears glasses instead of contacts. Both designs are great.
If you can afford them, the Pella glasses are really outstanding, especially those with the interchangeable
Zeiss colored lenses. They make a few models that can accommodate prescription lenses. Fine gear.