I should clarify "Middle Age Sight" for the folks in the 17-30 yr. age group.
I should have done this in my first post, but neglected to do so.
Sorry.
Middle age sight happens normally at or soon after age 40 for most of us. The eye's lens begin to harden somewhat making it difficult to focus. It mainly affects the near sight. Up close things were just a little out of focus and I couldn't get my eyes to clearly focus anymore. I could read magazines clearly if they were a little beyond arm's length away. I just couldn't get that up close sharp focus anymore.
It really sucked big time when it came to shooting because the iron sights I could see relatively clearly were now blurry. I had better than 20/20 sight so this was a big kick in the crotch to me. Reading glasses helped when reading and I could see the irons with clarity again, but reading glasses tend to make farther off things blurry. So now I could see the sights just not what I was shooting at.
At age 50, things at a distance have become
slightly out of focus along with my up-close clarity. I could still see it's just everything was now
slightly out of focus. Close up vision and far off. Hence my need for glasses. Now my 20/20 vision is back thanks to bifocals.
Unfortunately it's a chore to get bifocals to work properly when shooting long arms. So, now I'm putting optics on my most used long arms to compensate for that PITA problem.
The two Tritium dots will work, I think, because it's easier to stack a pair of dots than line up three dots. The three dots tend to get in the way of each other when they are all out of focus. It all becomes one big blur and you can't really tell if your elevation is correct or if they are lined up perfectly horizontally. Putting one dot on top of the other even when they are slightly out of focus is still possible, I believe. You won't have pin point accuracy but it'll be good enough at 0-20 feet.
I hope one of my local fun shops has a display with different iron sighting systems so I can test this out.