[nikolay]

I used the wrong term, sorry. My concern applies to both bifocals and progressive lenses, though: aren't drivers trading off convenience over safety? Shouldn't we have at least two pairs of glasses - one for driving, and another for everything else?

[sokoloff]

When driving, I need to see things far away (mostly) but also on my dash/instrument cluster.

I am near-sighted overall and have needed distance glasses all my driving life. I got progressives last year and driving is safer now as I have a small area that I can use to clearly (and quickly!) read the instruments, the radio (read: map), defroster controls, etc.

In my case, not having multi-focal lenses was prioritizing convenience/laziness/cost over safety.

[itishappy]

No worries, I understood your intent!

The impact is a lot less than you may expect. Brains are ridiculously good at filling in incomplete information. For example, did you know that you have a roughly sun-sized blind spot slightly off center in each eye (where the optic nerve attaches)?

Now imagine needing to switch glasses to read your dash. Inconvenient and unsafe!