Why is the ANTS target Sight frame curved?

It ensures that the lens in the scope is always square to your eye no matter what distance you are shooting. This in turn will ensure that the fiber optic pin in the lens is always pointing at your eye. The benefit of this system is two fold. First, if the lense is square to your eye, you will not be looking through it at an angle. Looking through it at an angle will distort the image you are looking at and can cause you to miss. Second, you will not see a the “double dot” prevelant in straight frame sights because the fiber is pointing directly at your eye no matter what distance you are shooting.