drgondog
Major
This may be of interest. This is a high end shooting glasses frame. The circle holds the lens, the black patch distrupts the vision from the left eye. I have seen light patches rather than black and in some cases just a stick like a matchstick.
http://www.stewardsportsglasses.co.uk/images/championworld4640.jpg
Me I am low cost. I wear normal glasses with the lens adapted to be ideal towards the top left of the right lens and a light cream coloured perspex attached to the sight that covers the forward vision of the left eye.
We have the same center of focus but for both right and left - my lenses are amber, violet and yellow depending not on light, but on background.
I still have Decot Lenses and frames I was given by US Army team (I was not on the team but I was second alternate behind Satterwhite and (Brad Simmons?? can't remember for sure, but he shot a Bauer shotgun), the two Olympic selections for 76 skeet team, and Tom Poston US Army who was first alternate.
We shoot a lot of flyers in LA and Texas and NC where there are frequently oak or pine trees outside the ring in lower light conditions and the grey pigeons are more diffcult to see in that environment. Ditto for shooting skeet and bunker trap and Powder Pigeon at Dallas Gun Club before trees were cut down.