Traditionally, the eyes are the windows to the soul. Thus, when we see a subtle emotion in someone's face, we say that we see it in their eyes.
It doesn't matter if we can really do this. We do read emotions off people's faces, in such fantastically subtle and sensitive ways that we're often not consciously aware of them. So, wherever it really is that gives them away, we say and often believe it's in the eyes.
On occasion, the things that we're told can be seen in someone's eyes can get really subtle or really abstract - from sadness or murderous fury all the way to humanity or the lack thereof or immense age.
This is a trope of literature and dialogue. You need this sort of description only if you can't see the person's eyes for yourself. Live-action works generally let you interpret for yourself; drawn works will often depict the emotions graphically.
Often a contributing factor to Uncanny Valley - viewers will say there's "something wrong with their eyes", and creators that they "can't get the eyes right". A good way to deliberately create an emotional disconnect is to hide a characters eyes entirely.
- In The World God Only Knows, when a student teacher gets a good look into Keima's eyes, she freaks out.
Jun: Expecting nothing from reality...those are eyes that are from another world looking in.
- Katsuhiro Otomo is a master of this.
- In Naruto the titular character realizes that Gaara's eyes are just like his own: Full of loneliness.
- In Magical Girl Lyrical Nanoha, the first that tipped off Nanoha that Fate wasn't as bad as she seemed was her "beautiful yet lonely eyes".
- Digimon Adventure has Myotismon outright telling Gatomon he hates her eyes and doesn't like her looking at him because they shine with hope, and it was something he tried to beat out of her.
- Played with in the 'Shining Armor' story from Astro City. Irene sees a glint in Atomicus's eyes, which she initially reads as a challenge, leading her to prod him about his secret identity until he leaves the planet, after which she understands it was fear. It seems more probable that the glint is just a glint in his eyes she can read however she pleases. He is radioactive.
- In Supergirl fanfic Hellsister Trilogy, Satan Girl and Berserkerís eyes show their lack of restrain or conscience.
The focus of the image came back to the lone warrior, or berserker, or... hell, just call him a murderer. His visage was less distinct than those of the Apokolips pair, probably because the computer didnít have a model from which to work. Still... the eyes. She could make out enough of them to see something there, a fury, a lack of conscience, a lack of superego with which to restrain the id.
Eyes that, in another face, could have belonged to Satan Girl.
- This comes into play in The Vow when Lord Shen proposes Lady Lianne shortly after their First Kiss. Before Lianne gives her answer, she wants to make sure the man she's about to spend the rest of her life with feels true love instead of temporary infatuation towards her. She does this by looking into Shen's eyes and searching from them a spark which according to the fairytales her mother used to tell her can tell you if the person truly loves you. Lianne finds from Shen's unguarded gaze not a spark, but scorching flames and agrees to marry him.
- In Big Eyes, Margaret explains that a combination of this and hearing loss she had in her childhood are the reasons why she paints the way she does.
- Played for laughs in Laurel and Hardy's The Bohemian Girl, where the exact phrase is used to justify touching the person's closed eyelids to read their fortune — so the "fortune teller" can pick their pockets.
- Discussed in The Force Awakens.
Maz Katana: If you live long enough, you see the same eyes in different people.
- The titular Winter Soldier in Captain America: The Winter Soldier has barely any lines and is wearing a mask over his mouth and nose for a significant portion of his time on screen, so most of the character's development comes through his very, very expressive eyes, along with facial expressions and body language. There is a substantial amount of meta online dissecting every minute expression he makes, much of it focused on his eyes.
- Priest uses this mentality as evidence that vampires are soulless monsters, as they lack eyes entirely.
- Harry Potter is the former Trope Namer, for the infamous "glint of triumph" Harry sees in Dumbledore's eyes in Book 4, which tipped everyone off that it's a huge setup.
- In Dragon Bones, Ward describes Oreg as looking at him with "wounded eyes". Ward didn't harm him at the moment, but as it turns out later, Oreg has lots of psychological issues from being abused by Ward's ancestors. His soul is, indeed, wounded.
- Juliet Marillier's The Sevenwaters Trilogy does this all the time, sometimes with more than one emotion at once, thus: "She saw a mixture of triumph and dread in his eyes."
- The last line of Richard Matheson's "The Splendid Source": the hero has just been invited to join the Ancient Tradition he's been tracking down throughout the story. He's all but speechless ... "But, already, the light of consecration was stealing into his eyes."
- Danny, the Champion of the World is one of many works to discuss the phenomenon of the "eye smile" - twisting the corners of your lips upwards looks nothing like a real smile unless the eyes are doing the right thing (which in real life is probably squinting slightly rather than reflecting the innermost workings of the soul, but Truth in Television nonetheless).
- Another Roald Dahl novel, Charlie and the Chocolate Factory, uses this trope with regards to Willy Wonka. In the detailed description of his appearance that opens Chapter 14 (in which he makes his first public appearance in years), his eyes are given special attention: they "were most marvelously bright. They seemed to be sparkling and twinkling at you all the time. The whole face, in fact, was alight with fun and laughter." This turns out to be a sign of his merry, mischevious Trickster nature.
- A major theme of Coraline, where the Other Mother has button eyes and wants to give Coraline the same.
- In Codex Alera Alerans can tell that something's off with those Taken by the Vord because there's something wrong with their eyes. Interestingly, Canim seem to have the same reaction with ears- one Canim character describes Taken Canim with "their ears didn't look right".
- In The Dresden Files wizards can see a person's soul with their Sight if eye contact is maintained (this is why you don't look at a wizard too long. They see too much). However, there's 3 drawbacks: the other person can see yours too, it only works once, and you never forget what you see. Ever.
- In The Lord of the Rings and the supplementary material, attention is often brought to Elves' bright eyes. From the descriptions they seem to invoke borderline Uncanny Valley in some characters, and especially evil-leaning characters are terrified from looking Elves' in the eyes, and even good-aligned mortals feel awe from them. The supplementary material explains explicitly that the fire of the Elvish spirit shines through their eyes much more strongly than mortal spirit.
- In The Wheel of Time series, characters get a hint that someone is evil or deceptive because they have a smile that does not touch their eyes. In truth, a genuine smile does contort the eyes, and it is apparently impossible to fake this.
- True enough. About half the muscles involved in a true smile are not under voluntary control. When you fake a smile these muscles don't activate, and since several of them connect to the portion of your skull around the eyes...
- A major recurring theme in Discworld.
- Going back to the very first book in the series, The Color Of Magic, is the idea the eyes are a clue to your true nature because they are the only part of your body that cannot be magically disguised, something true for gods as well as mortals. This becomes a plot point in Witches Abroad, where a character has to wear dark glasses to conceal the fact that he's a frog transmogrified into a human.
- This carries into Good Omens, though not a Discworld book, where Crowley the demon has Hellish Pupils that he hides behind permanent sunglasses.
- The inherent wrongness of the Cunning Man, the shade of a fanatical witch-hunter, is highlighted by his "eyes", which are simply empty holes.
- On the other hand this is thoroughly lampshaded in Going Postal, at least when dealing with the non-supernatural. Boxed Crook Moist Von Lipwig notes that "a firm handshake and a steady, honest gaze" are the most basic skills a con man needs, and he can deliver them on cue. The book's Big Bad, also a con man, has also perfected his (one-eyed) honest gaze... but that also confirms his completely dishonest nature when he tries it on Moist.
- When Elizabeth Wakefield meets the "evil twin" Margo in Sweet Valley High, she thinks that "If the eyes are the windows to the soul, this girl is evil because her eyes are cold."
- In Margin Play, Amber says this about Kasey during the meeting in the bar.
People say that the eyes are the windows to the soul; it's true, but only when the person being viewed opens that window. Charles Kasey chose that moment to, and I knew what I saw behind the black humor and artful apathy; something old and ugly and very human. Something society has always been too frightened to examine but depends on just the same. I wanted to look away but I didn't.
- In The Children Of Man, the color of a person's eyes indicates their magical talent. Blue mages have blue eyes, yellow mages golden eyes, etc. Brown eyes indicate someone who can use several magic talents, while Grays have reflective silver eyes.
- Appears in many different ways in The Stormlight Archive. First, when someone inhales the titular Light, their eyes start to glow as it leaks back out. Second, when someone becomes a Knight Radiant or bonds a Shardblade, their eyes turn from dark to light, and for this reason the lighteyes form the noble caste. Third, if you kill someone with a Shardblade (which "severs the soul" instead of cutting living flesh), their eyes burn up. Also the true forms of "dead" spren in Shadesmar appear to have their eyes scratched out like a damaged painting.
- In the third book of The Queen's Thief, after spending most of the book believing Eugenides to be ineffectual, vain, and irritating, Costis finds himself looking directly into Eugenides' eyes shortly after an unsuccessful assassination attempt. He describes it as things which are not hidden, but which Eugenides is choosing not to reveal, and is both unnerved and awed by the insight.
- Played with in the Doctor Who episode "The Time of Angels"; "The eyes are not the windows of the soul, they are the doors." As if those things needed to be even more terrifying.
- Terminator: The Sarah Connor Chronicles: "They say the eyes are the window to the soul. Your eyes look tired. Is your soul tired?"
- In one episode of Arrow, Fyers says he requires his men to wear balaclavas because then only the eyes are revealed, so his men are somehow more recognizable to him, which is how he can spot that Oliver is actually an intruder.
- In the pilot episode of George Lopez, George participates in a test involving firing his mother. He was unknown to the fact that it was merely a test, and when he figured out, he confronted her telling her he fired her and passed the test. She proceeds to deny it and George says "You know how you can look into someone's eyes to tell if they're lying?" After a brief delay, his mother says "Oh man, you fired me! You had the courage to fire your own mother; They finally dropped!"
- Parodied in NewsRadio, when Bill insists that "the eyes are the window of the skull".
Dave: I believe you mean 'soul'.Bill: For those who have one, yes.
- Eyes by Kaskade featuring Mindy Glendhill features the trope's name right in the chorus.
- Eagles "Lyin' Eyes:
I thought by now you'd realize
There ain't no way to hide your lyin eyes
- Asia's "Only Time Will Tell":
You're leaving now
It's in your eyes
There's no disguising it
- The Sanford-Townsend Band; "Smoke from a Distant Fire":
I know where you goin' to
I knew when you came home last night
'Cause your eyes had a mist
from the smoke of a distant fire
- Demons by Imagine Dragons:
When you feel my heat
Look into my eyes
It's where my demons hide
It's where my demons hide
- Legacy of Kain: "I swore I saw a glint of satisfaction in Kain's eye when the Soul Reaver was destroyed."
- In Fire Emblem: The Blazing Blade, Wallace decides to disobey his orders to capture "an imposter and two disloyal knights" when he meets them and declares that Lyn's eyes are too bright and true to be those of a liar.
- In Knights of the Old Republic II, the Jedi Exile doesn't appear outwardly scarred by their war experiences, but when conversing with a male Exile, Mira says that his eyes are years older than his face.
- In Fate/stay night: Heaven's Feel, Shirou knows that Rider is now his ally, but still feels uncomfortable around her- partly because she wears a blindfold all the time.
- In Metroid: Fusion, the SA-X is an exact physical replica of Samus Aran produced by the X Parasites, with the exception of its Blank White Eyes indicating its nature as The Soulless.