I have been in bifocals for the last 10 years or so. I've already done all of the things to my personal guns that I recommend to help your sights be more visible, but over time, the front sight was getting a little blurry and all I could do was tip my head back so I was looking through the bottom of my bi-focals. Not a great way to have to shoot!
Recently, I had my eyes examined and started talking with my ophthalmologist about not being able to get a clear focus on my front sight. I explained about tilting my head back and how this was not conducive to shooting. She was not a shooter, so it went over her head. But after I said, "you know, the front sight is about the same focal distance as I have with my computer screen and I have the same problem with the computer", she told me that I might benefit from a pair of “computer glasses”. I had brought in a blue plastic non-gun and she let me "aim it" while looking through the "Better or Worse machine" (you know the one!) until we tweaked the front sight into sharp focus.
In addition to new conventional bi-focals in my "street glasses", I had a second set of glasses made up with "computer lenses" in the top 2/3rds of the lense. That made an enormous improvement in my ability to see me sights! The computer lenses are between my upper and lower bifocal grind in power and I can now see my front sight like I did when I was a young man. So you might look into that too!
I also had a set of ballistic grade shooting glasses made, since I knew what kind of result I could expect. I had always been a little concerned about shooting with non-ANSII rated glasses, if something catastrophic happened. So I made the leap and contacted Decot Sports Glasses for a set of their "HY-Wyd" shooting glasses. A very knowledgeable lady named Laurie helped me and talked me through the options and took my order. A couple of weeks later, a package arrived from Decot. I am very impressed. I ordered the glasses with a set of clear lenses and a set of tinted lenses for outdoor use. The frame is durable, the lenses interchange easily. The kit included a rugged case, lenses cleaning cloth and solution. They convinced me to not do bi-focals on the shooting glasses and I'm glad I did. I can see well enough looking down to do everything that I need to without having the change in lense power which causes me to have to sometimes stop and refocus when I look down using the bi-focal computer glasses.
You can reach Decot Sports Glasses at https://www.decot.com
Update - 2020
I have been using both sets of the special glasses that I had made and I am delighted that I can see the sights like I did when i was a young man. One truth has come to me though. While these glasses work great shooting a handgun, they aren't anything I can wear on the street. So I am still doing my practicing with my street glasses and an HD front sight with a wide U notch rear sight. But the shooting glasses are on my noggin when I'm test firing customer guns, shooting IDPA matches or plinking.