One of the characters in my 5e campaign is a drow wild sorceror.
The party has been doing a lot of (daytime) wilderness adventuring.
The player and I are both getting a bit bored of him always rolling everything with disadvantage.
So, as I understand it, the sunlight sensitivity is impacting the fun of the game you are playing? Then of course let the player have a workaround! Debating whether a player should have to change characters or whether mechanical disadvantages should be compensated, etc. is completely missing the point in my mind. Is it getting in the way of the fun? Without it, is the character not so overpowered as to impact the fun of everyone else? If the answers are "yes", then find a way around it without hesitation!
The rules are there to serve the fun, not the other way around. Worring about balance is pointless - except when it impacts the fun of the game. Sounds like it is not fun for you or the player, and if finding a workaround doesn't wind up ruining the fun of the other players, then who cares??
I want this to cost ongoing resources, at least until the player can obtain the sort of magical resources it'd take a character of another race to get darkvision
Help!
Now, the real question - how?
Of course, this being an imaginative game, if sunlight sensitivity is getting in the way of the fun, you could just go Drizzt and "you've been in the daylight enough that you're fine now, penalty is gone" but there's options that are a lot more fun.
It sounds like the option 1 of darkened lenses seems like the best option, but you would prefer some sort of ongoing cost or other balance? Is it either because you want to make sure the character keeps paying for it, or just think the other options would be better for the game?
One way to balance the lenses is, being someone who wears glasses, I can't imagine going into combat and having them actually stay on my face. You could have it be an issue of whenever takes a melee hit there's some chance of them flying off and hitting the ground (and possibly breaking). To avoid extra rolling, which you seem to want, you could have something like any hit that succeeds by more than a certain number knocks the glasses off as well - or even 50/50 chance like odd to hit rolls knock them off or something. Sure, there's nothing like that in 5e, but if it has the outcome you want and keeps things moving without extra bogged down rolls, go for it. Or even any critical hit on the PC breaks the lenses, etc.
Or even some of the inuit sunshades people have posted could work and just have disadvantage to visual perception checks or reflex-like saves or some such - whatever makes sense having limited peripheral vision. That's one of the cool things about 5e is that you can just decide things like disadvantage on the fly based on real world common sense rather than strict rules.
But bottom line, I wouldn't worry about the naysayers stating the PC should just deal with it - if it is spoiling the fun, especially for you both, then ditch it without guilt.
I'm actually technically on the albino spectrum, suffering (as do many of my family) from ocular albinism a.k.a the real-world version of Drow Sunlight Sensitivity
Thanks! That was quite informative. I can see in some of these worlds drow possibly evolving similar eye traits, or even if not, it's useful to hear your experience. Thanks!