Shadowrun 5 is the one I know best and unfortunately a lot of that's changed
Specifically, Essence is now tied to your magic ability and maximum social limit. The maximum Magic stat you can have is tied directly to your Essence, and the calculation for it and the social limit round down to the nearest full number, not caring about the decimal
So even if you were to get say, cybereyes to offset a character's blindness or poor vision, which I believe is 0.50 essence cost, you go from your 6.00 maximum to 5.50, but every calculation takes it as going to 5.00. One point isn't a crippling loss for a build but starting from <5 and you'll start to have trouble doing anything magic or social