I have experienced eyes, and I used to use glue-in bifocal lenses. Here is s story that might tell you why I don't bother anymore.
I was part of a team doing exploration work in a cave, and I was working on clearing rock rubble out of a passageway. My work had made for poor visibility, but I could see reasonably well. All of a sudden that changed. I could see absolutely nothing after a cloud of silt rolled over me. What had happened was that our two deep exploration divers were leaving the cave, and they had brought that silt with them. They had both passed me in the tight passageway without my knowing it because of that silt.
Actually, only one of them passed me at first. The second one was right next to doing a decompression stop, but I had no idea he was there until I saw a Shearwater Petrel near me--and it wasn't mine. It was the diver doing the deco. I could see the computer, but I could not see the arm it was on. More importantly, I had no trouble reading his computer to see that he was doing a deco stop. (I was not using any special lens.)
I was already using Shearwater computers myself, so it didn't change anything for me--having such a computer had long since made extra lenses unnecessary. The only thing I have trouble reading on the Shearwater is the tiny print that lists all my gas choices during a gas switch, but there is a different mode I could use instead that is easier to read but does not have the functionality I prefer. If you are not doing multiple gas switches during a dive, that won't be a factor.
