The EyePal is a new product that claims to bring the rear sight, front sight and target all into focus at the same time.  The EyePal is a small disk that attaches to the front of your shooting glasses.  The disk has a tiny hole, or aperture, in it that allows the eye to focus on more than it could otherwise.

As I understand it, this is the same effect that a photographer uses to adjust depth of field through aperture size adjustment.  A photographer can capture a very shallow depth of field (sharp subject, blurred background) with a large aperture such as f2.8.  With a smaller aperture, such as f11, a lot more of the scene is in focus.

It appears that by forcing the eye to look through a tiny hole, it allows the shooter to perceive more of the target and sights in focus.  I would presume that you would need good lighting to effectively use this device.  MSRP is $29.95.