Them Bicycle-focals make shootin' harder than it has to be. Spring for a pair of straight glasses that will allow you to focus on the front sight. When it's real noisy I like to put earplugs in under the ear muffs. Justsome hints I picked up along the way.
Before you spring for those single vision or even progressive allow your optometrist to show you what the rest of the world will look like - it ain't pretty.
Last time I went in to get a new prescription I asked the doc to set it up so that there were three focus points, reading, shooting, distance. He asked why and I told him. He told me he was a shooter too and that setting up trifocals like that or bifocals with the close set to the front sight range would be very uncomfortable. He showed me what it would look like while I was on the machine. Trifocals was kinda OK but confusing, bifocals - no way - wouldn't have been able to read with them and single vision set to sight range - ROFLMAO - no freaking way. Not for me.
So have your optometrist give you a look see before spending $300 or $400 on shooting glasses.