Do a search on AT for "verifiers and clarifiers"- one will clear up your pins, while the other will clear up your target. Those of us who use magnification in our sites (3D, target, and some hunting) and some who's vision has deteriorated over the years have to use them. They are no magic bullet or quick fix, you have to play with them together with the size of the aperture to get the desired result.
Your best option is install a peep made by Speciality Archery Products. I have the standard non hooded on my bow. With this peep you can change the aperture size as well as installing a verifier or clarifier. If you have no lens in your sight scope than it sounds like you need a low power verifier like a #4 or #5. I recommend going to the Speciality website and looking at their products and their video on verifiers. Their stuff is not cheap, but once the peep housing is installed you just simply unscrew and screw in the different apertures. Another thing that can help with blurry pins is always concentrate on the target and never look at your pins and a single pin sight will also help. Focus on the target and let your subconscious mind be aware of your pin. Extending your sight farther from your bow with an extension bracket helps if your farsighted. A smaller peep will also help concentrate your vision kind of like squinting your eyes, but a smaller peep allows less light in during low light hunting conditions. Like Hittingguru said when your eyes start to go you have to try a combination of peep sizes, verifiers, clarifiers, and lens for your sight to find what works for you.