Disclaimer: I own nothing.

Notes: I received two fic requests from Alioseven over on AO3 last month. This is the second one. This prompt asked for Sherlock/Lestrade, with one of them wearing glasses and the other finding it attractive.

Warnings: Non-fatal illness, mentions of blindness, and taking extreme liberties with the original prompt. Title is taken from "Sunday in the Park with George."

The first time Lestrade notices that something is wrong, they are at a crime scene.

Isn't that always how it goes?

Sherlock has to bend too close to read something, and the gesture imprints itself on Lestrade's mind. It's not as though it's unusual-Sherlock is older than he looks, after all-but this tiny chip in his ongoing determination to separate himself from ordinary people reverberates like a bell in Lestrade's head.

The second time it happens, they are in his office, and Sherlock is squinting at the paperwork. John points out where Sherlock's supposed to sign, slightly amused. Sherlock Holmes has bad eyesight - who would have guessed the man had a weakness?

Just transport, indeed, and Lestrade can hear John teasing Sherlock about it all the way down the corridor.

But while John is unconcerned, Lestrade can't let it go. He doesn't know why. Perhaps it's because it isn't long before Sherlock starts conceding to his genetics, and brings along reading glasses when he comes to the Yard. Eventually, he starts wearing regular glasses full-time, and while they look good on him-far better than they have any right to be, in fact-Lestrade can't shake the feeling of faint unease. Sherlock isn't ignoring this particular need of his body's, like he does with food and sleep, and Lestrade finds this peculiar.

Perhaps he shouldn't, because Sherlock's life is his eyes; in what he can observe and deduce.

Lestrade watches him, then, at crime scenes. The changes are subtle, if they are changes at all and not a figment of Lestrade's overworked brain. Anderson once accidentally shines a torch in Sherlock's eyes, and he shies away from the glare when normally he would have stared Anderson down until he moved the light away. On a couple of cases, when they come into Lestrade's bright office from the stifling dark outside, Sherlock takes longer than usual to adjust, and once even grabs John's elbow for guidance.

And then, there is the exhaustion.

More than once that spring, Lestrade calls Sherlock late in the morning only to be greeted by a groggy and less-than-awake consulting detective. And gone are the days when Sherlock would stay out all night, dragging John on a wild chase through London. John seems relieved when he tells Lestrade this at one of their pub nights-he can't get over how nice it is to have the flat quiet from eleven to six, seven, eight-but Lestrade frowns, because though he doesn't rub John's face in it, he has known Sherlock longer. And the Sherlock he knows-had known-scorned sleep for work, and very rarely suffered for it.

He's asleep one afternoon when Lestrade comes trudging up the stairs to 221B. Receiving no answer to his knock, he takes out his key and lets himself into the flat, already suspecting what he might find.

Sherlock is stretched out on the sofa, an arm thrown over his eyes, legs bent at the knees and his feet shoved into the crack between the cushion and the arm. It takes Lestrade shaking his shoulder to wake him, and even then he is slow to rouse. Lestrade moves into the kitchen and puts on the kettle, and by the time there is tea Sherlock has woken sufficiently and shuffles into the room, eyes bleary behind his glasses.

"Thank you," he mutters, accepting the proffered mug, and Lestrade raises an eyebrow at the absentminded kindness but doesn't comment on it.

"Got a case for you. Busy?"

"Not nearly enough. What've you got?"

Lestrade outlines his case, but Sherlock's mind is elsewhere. He nods and hums at the appropriate spots, but his gaze is fixed at a meaningless spot on the floor and his hands remain curled around his mug, which he doesn't drink from again.

Finally, it is too much.

"How long have you known?"

Sherlock blinks, and raises still-bloodshot eyes to his. "Known what, Lestrade?"

"That there's something very wrong with your eyes."

For a moment, the kitchen rings with Lestrade's words. Sherlock straightens, and fixes him with a glare. It is too fierce, and Lestrade knows at once that he is right. His heart clenches.

"Just because I wear glasses?" Sherlock scoffs. "Honestly, Lestrade, I knew you were never very good at deducing, but even that is a poor conclusion by your standards. Hell, even you wear glasses - "

"That's different," Lestrade says softly, interrupting him. "I wear glasses to help me read. You wear them... and they don't help you at all."

Silence reigns for another endless moment-and then Sherlock sags, dropping one hand to the counter and leaning his weight on it, as though it's the sole thing holding him up.

"Go on," he says finally, dully. "Gimme."

Lestrade outlines what he's noticed, and then says, "It's a disease, I think. An injury would have brought this on all at once, probably, and you've been -"

" - experiencing this for some time, yes." Sherlock continues to speak in that same, colourless voice. He sets down his tea, runs a finger around the rim, and then says, "Retinis pigmentosa."

"Curable?"

Sherlock shakes his head. "Degenerative."

"How bad?" When Sherlock says nothing, Lestrade's heart stutters. He ventures, "Blindness?"

"Unknown," Sherlock says, faintly bitter but mostly resigned. "I will lose my peripheral and central vision. Complete blindness... well, it's possible. And I might as well be blind, for all the good I'll be to you when this is all over."

"Don't say that," Lestrade says automatically, and then immediately regrets his words, because they can't pretend that Sherlock will be able to perform his duties as usual. It's unfair to them all, especially to Sherlock.

"You are too kind, as ever, and quite delusional. We both know that it's only a matter of time before I can no longer work your crime scenes."

"We'll figure something out," Lestrade insists, unsure of who he's trying to convince. Sherlock says nothing in contradiction, allowing them both this illusion.

"John doesn't know," he says eventually, changing the subject, "and I'd rather you not tell him."

"I wouldn't do that," Lestrade says, slightly hurt, and Sherlock nods absently.

"Yes. I know." He rubs the back of his neck wearily and then adjusts his glasses. Lestrade feels a pang then, because up until now, even amid his confusion, he had found them rather attractive on Sherlock. Now, they serve as a reminder of the one thing Sherlock holds dear, and what he is being robbed of. "Was there anything else, Lestrade?"

"N - ye - um..." Lestrade trails off, torn between three different answers and giving none. Sherlock's lips quirk, and it's the closest thing to a smile that Lestrade has seen on him in weeks.

"Eloquent, as ever," he says dryly, and Lestrade smiles with him.

"Yeah, just, um... if you ever need anything..." He trails off again, but Sherlock nods in understanding.

"Yes. I know that, too."

Lestrade is halfway over the threshold when he turns on his heel and doubles back.

"Have you ever seen the Milky Way? Actually seen it properly, I mean, not just in a picture from a book?" he asks-demands, really-as he strides back into the kitchen. Sherlock looks up from his microscope, and blinks stupidly. Lestrade doesn't give him a chance to reply. "Look, it's just-I've got some days off coming to me, and I was thinking about a trip to Exmoor. Great stargazing, away from the city and all, and it wouldn't be for more than a couple of days. You know, if you were interested -"

Sherlock's quiet, "Yes," uttered just after Exmoor, goes unnoticed by Lestrade until he's talked himself out of breath. He stares at Sherlock as the words finally register.

"Yes?"

Sherlock shakes his head and turns back to his work.

"I was wondering," he says at last, "how long it was going to take you. You've been ogling me in these damned glasses for ages."

Lestrade stares at him, dumbstruck. Sherlock goes on.

"Come now, don't look so baffled. There is a reason, after all, why I will only work with you."

And just like that, he is dismissed.

Lestrade leaves, grinning stupidly all the while, and lives off those words for the next three days.