First off, it will totally depend on the each persons vision and/or limitations. Trust me on this, I have been fighting it for a while now.
What I have found out is, when you go to the eye doctor, they have to make a formula equal out, when it comes to bifocals and/or trifocals. Its like an algebraic formula. To gain something, you have to give up something, in certain situations. I have been complaining about not being able to see as well since I began wearing bifocals/trifocals. I wanted to get my distant vision back, and I did, but at the cost of giving up my trifocals. So now I must wear trifocals to see open sights (to shot and hunt) and I use just my bifocal glasses for normal day use. With my trifocals, my distant vision is not as good, but I can see open sights fairly clear and definitely have improved distant vision with just bifocals.
Without a speck of doubt, peep sights and a front sight of the optimum size for the peep works best for my vision and is now is paramount.
It would behoove you to discuss this with a good eye doctor.
One last comment on this. My Lyman GPR has a buckhorn rear sight and a fairly wide front sight. I can actually get a fairly good sight picture while wearing only bifocals. So indeed, buckhorn sights can be beneficial in certain situations.
Good luck to you.