Progressive Lenses and Large Monitors Do Not Play Well Together
Age chews up the eyes. If you wear glasses then at some point, on roughly the same timeline as noticeable graying starts in on your hair, you are going to develop the need for different prescriptions for computer use versus other activities. You'll notice because of a growing eye strain while coding, and eventually that will drive you to visit an optician. After sticking you in front of eye charts, shining lights at you, and so forth, that individual will no doubt try to sell you on a set of progressive lenses.
When dealing with the need for different lenses for close and distance vision there are three options: firstly two different pairs of glasses that you swap out as needed, secondly bifocals, and thirdly progressive lenses. A bifocal has two distinct parts of the lens for use at different distances, while a progressive lens has a gradual gradient of changing focal properties from top to bottom and also from center to edge. As for bifocals the general idea is that the bottom center portion of the lens is for close vision and the top is for distant vision.
Progressive lenses initially do some interesting things to your vision. While your brain is still adapting it looks like the world is slanting and sliding at the left and right edges of your visual field. That goes away in a few days, or even faster for some people, and remains gone even if you later switch back and forth between normal and progressive lenses. A few people don't adapt well and continue to have issues, but the only way to determine whether you are one of them is to try.
The ideal activity to show off the utility of either bifocals or progressive lenses is driving. You are sitting in a position in which the top portion of your field of vision - through the windshield ahead, or looking at the rear view mirror - consists only of distant objects. The lower portion of your field of vision consists only of near objects, and all of the important items on the dashboard are in the central lower area right in front of you where the lens properties are best. Without moving your head you can turn your eyes to either of these areas and get the best corrected vision. That is still fairly true even when turning to look to either side or over your shoulder for the blind spot.
Progressive lenses and bifocals fall down badly for development on a large monitor, however. When working with code or other development concerns your head typically doesn't move all that much but you will frequently shift focus rapidly between widely separated areas of your field of vision. In a typical development environment there are code blocks and indicators and command prompts all over the screen: you are not just focused on a single area. The problems this causes should be obvious and self-evident for bifocals: most of the monitor falls into the long-distance section. If you want to see up close, you have to move your head constantly where previously you only moved your eyes. It is far worse for progressive lenses, however, as the outer corners of each lens are distorted. They are not intended for use at all, but if you are working with a large screen you have to use those sections of your visual field. The only alternative is again to move your head constantly where in the past you just moved your eyes.
To move your head rather than your eyes is distracting to the point of madness. It simply can't be done efficiently, instinctively, and rapidly enough to be feasible for in-the-zone development. Or indeed for any development activities. Try it sometime.
So in summary if you spend significant amounts of time in front of a monitor, don't go for progressive lenses or bifocals when the time comes. You will regret it. Instead use two separate pairs of glasses, one for computing work and one for everything else, as that is the only way to maintain good close vision that allows you to continue rapidly move your focus around a large screen without having to change the way in which you presently move your head.