I found a new purpose for an old pair of eye glasses. If you wear bi-focal glasses, and use a scope, sometimes you will see two crosshairs because your eye or head is not alined behind the scope properly. This made me ask why my fiber optic sights on my shotgun blend togeather and are not sharply defind anymore. This gave me the idea to try a pair of old pre-bifocial glass'es that I kept from ten or fifteen years ago. And guess what? The fiber-optic became as sharply defined as before. The anti-glare stuff can also cause problems seeing things sharply. All you young guys who don't wear bi-focal lens (yet)better keep the old glass'es. Mine has made a big difference. Sure glad I did. cluck