This is one of those situations where I'd go with narrative fulfillment, rather than a mechanical one. If there's a cleric in the party (or someone else whose narrative abilities are healing the injured or infirmed) and they have someone who has been blinded and without eyes... I personally wouldn't just look at all the various healing spell descriptions, find the one that "applies", and then say "Well, sorry, this is the only way to do it, so you can't until you have mechanically reached the proper XP to finally "receive" this spell." That seems much too beholden to the "game" rather than the story and is not something I actually like doing.
If you have healing abilities throughout all 9 spell levels... narratively-speaking there should be a progression of what a person could accomplish. So to me... the idea that at a "2nd level spell slot" a healer could restore the sight of a blinded person (who had their eyes), but that same person couldn't fix the eyes themselves until using a "7th level spell slot" is just narratively wayyyyyyy too big of a jump. Especially considering that in that time, these healers can not only restore life to a dead person, but also completely reincarnate someone by creating a whole body for them? They can do all that... but they can't somehow just fix a person's broken eyes.
To me... that's just another point where being beholden to game mechanics for the sake of game mechanics results in incoherent story and gameplay. And a much less satisfying... and dare I say it... to me, a stupid game.
"Yeah, I know you had your ear burned off by that acid... but I can't replace that ear. So instead I'm going to create a whole new body for you, kill you, and then put your soul into it. Because that's easier."
Nah. Forget that ridiculousness. If a 2nd level slot can restore blindness, then a spell a couple level slots higher can give someone their eyes back-- either straight away if you don't want to roleplay the story, or by sending the group on an adventure to get the items necessary to create the invented ritual that would allow it. Make the eye restoration part of the story, not just a hurdle that the group has to play through over months just to earn "XP" so they eventually "get" a fix for it.