Quote Originally Posted by narsuitus
1. The Nikon screen with the grid lines and the split image is the E screen. The R screen has the grid lines and the split image focusing aid.

2. From what I understand, Nikon makes 3 to +2 diopters for the F3HP. This should cover both near-sighted and far-sighted people. However, unless you can actually try the diopter on your camera, it is not a simple task trying to calculate exactly which diopter will correct you particular vision problem. I use a +1.75 diopter reading glasses so I figured that a +2 diopter should help me. Wrong! The +2 diopter that I ordered made things much worse.
Getting things in focus with an SLR is a nightmare if your vision is faulty, because the whole system depends on the user having perfect eyesight, so in some cases a split image might be apparently in focus in the viewfinder, but out of focus on the film . Eyesight correction lenses can help sometimes depending on what defect the person has ( I have astigmatism and find that a correction lens is fine in the horizontal format, but as soon as I turn the camera into the vertical format the viewfinder image goes out of focus ) I find personally the best option is to wear glasses. You mention in your post the Nikon F3 HP which has the high eyepoint viewfinder, you should't have any problem seeing the whole screen with glasses with this model.