I think it isn't a "too focused" effect so much as an "any focus" effect. It's just a matter of degree.
And that darkness, that wraparound blind spot. It doesn't exist. You know what I mean? It, in all likelihood, is not accounted for at all in your reality.
I mean, you don't say to yourself, "gosh, I'm blind to all this stuff". No. the stuff just doesn't exist.
And add habit to the mix, that subconscious robot. Habit that governs this universe-dividing attention.
Titanic feats of reality-conditioning could be happening right under your nose, constantly. And you'd never even know it.
As someone on the medications, all it seems to do is just activate my hyperfocuing abilities more consistently. I just have to cross my fingers that the stars align so I hyperfocus on what I need to focus on and not play Jedi Survivor for 6 hours straight.
I'd only suggest doing that once every 2 week, and sleeping normally at least each night for the week before for maximal results.
Also, it's a bad idea to code when tired (due to risks of negative productivity): it's better to just think and take notes, draw diagrams etc
BTW I've heard people who are on ADHD drugs report a similar "too focused" attention: a very narrow beam on a very bright spot.