Universal Eyeglasses describes the phenomenon in which a character is able to experience vision correction using any form of corrective lenses, even those not prescribed for them. In reality, the range and extent to which one suffers from nearsightedness, farsightedness, astigmatism, or any other ailment that impairs vision varies from person to person. Ideally, a number of tests are performed on an individual to determine the type and strength of the lenses required for vision correction. Afterwards, the frames of the glasses must be properly adjusted so that they can be worn without the risk of slipping off the face of the wearer. This is not always the case in fiction. The trope typically goes as follows:
Bespectacled beauty and Cool Teacher Alice asks her student Bob to read what she has written on the board. However, something seems wrong. Bob is squinting more than usual. In response, Alice knowingly takes off her own glasses and puts them on Bob's face. He is able to read the board perfectly.
Does it matter that Alice is much older than Bob? That they might have differing facial structures? That their vision may be impaired to differing degrees? Or even in radically different ways? Not at all. If this trope is in play, the eyeglasses will always work.
Though often executed via a character giving their own glasses to another, this trope also applies to the more extreme instances in which glasses are taken from a toy or something similar. This is especially notable since glasses worn by playthings aren't prescription made at all and therefore shouldn't be able to function as if they are.
Compare Glasses Curiosity, as the two can and sometimes do overlap provided a character is able to see perfectly while wearing someone else's glasses. Compare One Size Fits All for clothing wearable by anyone despite individual differences in size and shape. Blind Without 'Em and Dropped Glasses are common catalysts for this trope as well. Contrast Purely Aesthetic Glasses which aren't meant to provide any amount of vision correction. A subtrope of Artistic License Biology.
- Naruto: When Kabuto arrives at Konoha's Orphanage, he is required to read the clock to ensure that he's getting a full grasp of the schedule to which they adhere. The nun who runs the orphanage notices that he's squinting and gives him her glasses allowing him to answer correctly.
- Used in Dr. Stone. Suika is extremely short-sighted, so Senku crafts a set of corrective lenses for her, built into her watermelon helmet in place of actual glasses. During the tournament to decide the next chief of the village, her watermelon helmet winds up on Kinro's head, correcting his vision and allowing him to win his match. It also allows him to admit that his eyesight is less than perfect, but it is implied to be nowhere near to the same degree as Suika, whose lenses logically should have overcorrected.
- Kaguya-sama: Love Is War: After discovering that Shirogane is nearsighted, Hayasaka has him try on her glasses and he immediately comments on how much clearer things are. Although there is at least some justification as the quick vision test she gave him led her to suspect that they had a similar level of myopia.
- Alvin and the Chipmunks: Dave gives Simon a pair of glasses from a Santa Claus decoration after noticing his uncoordinated behavior. They instantly correct his vision. Subverted later when Ian switches the glasses for cool shades, as Simon could barely see with them.
- Adventures in Babysitting has a girl take her glasses off and set them down. The person sitting next to her picks them up and tries them, and discovers (one assumes) that they work perfectly; the thief leaves her own glasses in place and scarpers. The victim is of course Blind Without Them.
- Brooklyn Nine-Nine: Averted. Amy and Jake recall having swapped contact lenses once by mistake and thought they were having strokes due to the severe difference in their prescriptions drastically messing with their vision.
- Zig-Zagged in Lost. When it turns out Sawyer needs glasses, Jack scrounges up as many leftover pairs from the crash as possible and they spend a whole scene trying out different ones to find a match. Eventually they resort to having Sayid weld two lenses from different pairs together. It's then played straight in season two when Sawyer suddenly finds a pair that are a near-perfect match.
- In the "Cleveland Rocks" opening segment of The Drew Carey Show, Drew's glasses get broken. The sequence includes Drew and his friends going to the Rock & Roll Hall of Fame and stealing the glasses of off the Buddy Holly statue, which appear to be perfect substitutes.
- In Fallout 2, a shopkeeper is having vision troubles because his glasses broke. You can fix this by giving him a random pair of glasses you find in a refuse pile in another town. They work perfectly.
- In Fallout 4, the character earns Perception Bonuses each time he wears the relevant glasses, notwithstanding the kind of corrective glasses he wears or the existence of any visual issues.
- Fallout: New Vegas: Characters with the "Four Eyes" trait have a +1 bonus to Perception while they're wearing glasses, and -1 Perception while they're not. Any pair of glasses will provide the bonus, including sunglasses and the goggles worn by Lobotomites.
- An early puzzle in Monkey Island 2: LeChuck's Revenge requires Guybrush to steal Wally the cartographer's monocle, which he can't work without. You later have to replace it — with the focusing lens from a model lighthouse, which is of course a perfect match.
- Overwatch: In the "Recall" cinematic, Winston uses Dr. Harold's glasses so he can see out of the window. When we're shown his perspective, his vision is perfectly clear with the glasses but blurry without them. As an adult, he wears a similar pair at all times.
- In Paper Mario: The Thousand-Year Door, grumpy chef Zess T loses a contact and demands everyone stop moving while she looks for it. The game leaves Mario no choice but to move or jump, and he inevitably steps right on it. At this point Zess blocks the archway into east Rogueport until Mario buys her a replacement from a local bazaar — no prescription needed, but it takes all of Chapter 1 to arrive.
- Professor Layton and the Azran Legacy: One of the side trips in chapter four is solved by giving the village chief a pair of glasses. That the professor made himself out of some crystals. Without even so much as asking the chief or anyone else if his vision is bad.
- During a Chain of Deals in Yakuza, a homeless man is given a coat that the player got in an earlier trade. The homeless man rewards the player with some eyeglasses which the player then takes the glasses to a business man wanting to see a strip club. The player gives the glasses to the business man, without questioning the prescription.
- An episode of Adventure Time sees Finn try to increase his intelligence in order to impress Princess Bubblegum. He obtains a pair of glasses from Choose Goose. Said glasses endow the wearer with supreme intelligence and with insanity. Finn's vision is pretty much the only thing that remains unaffected by them despite the fact he doesn't usually wear any sort of prescription (thus his vision should have been a blur) and obtained them from an acquaintance.
- In Elliott from Earth, Frankie gives Moe her glasses after he fails to notice that there are frogs in what he previously believed was a talking hole. Her glasses fit him perfectly and correct his vision entirely despite him being a dinosaur.
- Ego Trip: When Number Twelve (a wimpy future version of Dexter) gets his glasses knocked off and stepped on by Executive Mandark, he snaps, beats up his foe, then takes E.M.'s glasses for his own.
- The Fairly OddParents: In "Knighty Knight", Timmy goes to Camelot and meets King Arthur Liebowitz, who is a boy with bad eyesight. Timmy later gives Mr. Turner's reading glasses to Arthur, giving him perfect vision (as well as a muscular body to fight a dragon with).
- Sofia the First: Sofia's friend Jade is suddenly terrible at dazzleball. When Baileywick's glasses get knocked off, Sofia suddenly realizes that this must be Jade's problem and asks Baileywick if he has any spares. He does, and suddenly Jade's back to being the best player on the team. While Jade does mention that she's going to go to a doctor to get a proper prescription, it doesn't explain why an 8 year old girl whose vision is fine outside of a sport that relies heavily on hand-eye coordination is helped by wearing the same glasses as an older-middle-aged man who's practically Blind Without 'Em, nor how glasses fitted for an adult's face manage to stay on while she's running, jumping, and sweating (which has to be accounted for even on properly fitted glasses).
- The Wild Thornberrys: The episode entitled "Pal Joey" has Eliza agree to babysit a mischievous kangaroo named Joey. It quickly becomes too much for her to handle due to his manic behavior. At one point he steals her glasses, places them onto his own face and declares himself a "Googly Human". He has no trouble using them and they fit him perfectly. Unfortunately, poor Eliza is Blind Without 'Em (implying that the lens prescription is strong enough that Joey really ought to be blind with 'em).
- Truth in Television up to a point — even a weaker or slightly stronger prescription not made for a given person can be better than nothing at all. But if the lenses are too strong, made to correct farsightedness instead of nearsightedness or vice-versa, made for a person with noticeable astigmatism, etc, then they might not be much use.
- A related phenomenon in fiction is the idea that any pair of glasses can be used to focus light down to a point like a magnifying glass, typically to start a fire. In reality, this only works with cheap drugstore magnifier glasses, or specific prescriptions for farsightedness. In particular, nearsighted lenses have a negative focal length, which diffuses light rather than focusing it.