A party member was blinded in a fight I shall not name (no need to spoil).
He could not do any attacks at all : neither using a dagger on an adjacent target (who was sleeping), whether manually clicking the attack button or clicking directly on the target. I could also not use a ranged cantrip. For those who do not know the mechanics : the description in-game of the Blind condition and the 5e rules both state you have Disadvantage on attacks (and you also, in 5e rules, lose the capacity to do Attacks of opportunity). But in this case, he could do nothing at all (luckily my cleric did the spell Restoration).
Steam profile : https://steamcommunity.com/id/baraz/