Presbyopia is not the reason one cannot see through a rifle scope. Presbyopia is why one cannot see iron sights. Presbyopia is why one needs magnifier or bifocal to read. Presbyopia is why some older folk can see far away, but not up close.

Presbyopia doesn't keep one from being able to see the target and/or cross hair in a rifle scope. The rifle scope may be right up next to the eye, but the image of the target and the cross hair are far away. The image the eye sees in a rifle scope is at infinity so to speak. People with Presbyopia can see the target and cross hair inside the rifle scope clearly, if the cross hair is focused correctly, and the rifle scope is working properly.