In Real Life, partial ("red-green" or "blue-yellow") and full color blindness are among the most common disabilities, affecting around 8% of males and .5% of females worldwide, with the number possibly being even higher as many people go through life unaware that they have the condition due to it not causing problems in their lives.
In fiction, however, a character having this is usually a Chekhov's Gun or is only brought up in a situation where being able to distinguish colors is vitally important, such as a Wire Dilemma or needing to identify a key object by color alone. The fact that color blindness is usually inherited means it can also be used to prove or disprove a character's parentage if they have it while another character does or does not, though much like the AB Negative trope the mechanism of inheritance is often over-simplified, especially with females who are far more likely to be an asymptomatic carrier for the condition unless they get it from both sides, due to the most common gene associated with the condition being carried on the X Chromosome. It's also sometimes used as an explanation for a character's horrendous fashion sense, in which case it's often Played for Laughs. Since color blindness can disqualify a person from receiving certain types of licenses, especially aircraft, a character learning they have this is sometimes used as a Dream-Crushing Handicap.
May also occur with Funny Animal or Uplifted Animal characters pointing out that their species is naturally color blind as a Furry Reminder. When this trope is applied to dogs it's a case of Science Marches On, as it's now known that while dogs may not see colors as well as humans they're still able to distinguish them.
Compare Blind Mistake, where a character being unable to see at all causes confusion, and Animals See in Monochrome (which often uses this trope). Not to be confused with Colorblind Casting, where an actor's race is not taken into account when casting a role.
- In SEX, Yuki's red-green color blindness contributes to his Drives Like Crazy tendencies since he pays no attention to traffic signals.
- Combined with Imposter Forgot One Detail in Magical Girl Lyrical Nanoha A's. Being cats, the Liese twins get the color of their Barrier Jackets wrong when they disguise themselves as Nanoha and Fate. Not that it really matters, since the person they were trying to fool had never seen Nanoha or Fate in their Barrier Jackets, but it clues in the audience that something is up.
- In Tongari Booshi no Atorie, a boy named Tartar has a condition where he can't see colors called argentosis. This ends up biting him since when an accident scatters the bottles of paint ingredients and leaves them disorganized. Worse, he encounters a situation where he needs to give someone medicine but because the bottles aren't labeled he runs the risk of giving them something dangerous instead.
- It's not brought up often, but Cyclops is effectively color blind as a result of the ruby quartz visor that's used to keep his eye beams from destroying everything tinting everything a shade of red. How he's able to fly the Blackbird isn't explicitly stated, though it's likely the controls have been calibrated so he can see them.
- The Rainbow Raider, a member of The Flash's Rogues Gallery is a gifted painter who's also completely color blind, which hampered his success and eventually caused him to turn to crime.
- In Top 10, Hyperdog eventually reveals that he's color blind, which means that he's been able to see through the patterns on the skin of his partner Girl One (who was created by a couple of horny fanboys so she has to be naked all the time but does have a nudity taboo and uses the patterns to give her some modesty) and when she finds out he's been effectively seeing her naked this whole time she decks him. He tells her he's not attracted to human women as a way to try and defuse the situation, though we later learn he was lying about this when he enters a relationship with a human and adopts a daughter with her.
- In the Colt Noble story from Mini-Comics Included, Mareea is fooled by Duper, an impostor Colt with green skin and purple hair. Her brother Ferran confirms the obvious at the end of the story — she's completely colorblind. If this sounds a little weird, read up on a Masters of the Universe character called "Faker".
- In Cats & Dogs, the dogs know which color wire to pull on a bomb to disarm it, but since they're all color blind can't tell which one it actually is.
- Ed Wood has Ed being forced by Loretta to choose between a red and a green dress, but when he can't decide asks the director of photography to choose one or the other, only for him to reply that he can't tell them apart. Doubles as both a Breaking the Fourth Wall joke as the movie is Deliberately Monochrome and a reference to Wood's real-life director of photography Bill Thompson, who was actually color blind.
- In The Hangover Part III, Chow being color blind means that he can't tell Stu which wire to cut when both are trying to disarm two parts of a security system at the same time.
- A unique example turns up in The Abyss. Bud isn't naturally color blind, but his only illumination source in the depths is a pale green light that makes the wire he has to cut look exactly the same as the one he shouldn't cut.
- In Little Miss Sunshine, Dwayne wants to be an Air Force pilot and has taken a vow of silence until he succeeds. Finding out he's color blind and therefore won't be able to fly causes him to drop an Atomic F-Bomb.
- In The Shadow, a color blind scientist cuts the wrong wire on the nuclear bomb, making the timer go to warp speed. By the time he's reconnected that wire to fix it, he's gone from having hours to having about two minutes.
- In Strange Days, evidence is discovered that the killer must be colorblind. It never gets to be a useful clue because the colorblind guy kept it a secret, but serves as a Brick Joke in the final confrontation, where the killer tells the protagonist his color blindness is the only way one can stand the latter's taste in clothing.
- In Shrek, Fiona sends Donkey to find a blue flower with red thorns to help heal Shrek after the ogre takes an arrow to the butt. Cut to Donkey desperately looking around a field of those exact flowers before complaining that "this would be so much easier if I wasn't color blind!"
- In The Giver, all of the members of The Community are color blind since birth, and have apparently been deliberately made so through genetic engineering. When protagonist Jonas realizes this and specifically that he can see the color red while they can't it contributes to him finding out the truth about their way of life.
- In John Doe, the title character was completely color blind except when he saw certain clues or people related to his previous life or the case he was working on, when instead of the usual Deliberately Monochrome style the show used from his perspective the items in question would be in color. There was also an episode where a lightning strike restored his color vision but made him lose his Encyclopaedic Knowledge until another lightning strike put things back to normal.
- In the Leverage episode "The Lost Heir Job", Ruth's color blindness is hinted at when she brings flowers for a grave and calls them blue irises when they're clearly yellow. This is later used to prove that she's really the daughter of the wealthy Mr. Kimball and a stripper named Georgia, who were both color blind and correctly shows the mechanism of inheritance as coming from both sides.
- Mister Ed: The title character had whether or not he was color blind flip-flopped with two episodes touching on it, the first where Ed wants a color TV but Wilbur refuses to get him once since horses are color blind, but Ed proves him wrong by pointing out the color of the clothes he's wearing. In a later episode Ed wins a color TV in a trivia contest, and a fight among Ed and Wilbur ensues about whether it will go in the house or the barn. In the end Ed steals the TV and watches it in the barn, and decides to let Wilbur have it, since he discovered he was actually color blind.
- On season 9 of Project Runway Anthony Ryan Auld, a fashion designer featured as a contestant, is color blind, and talks about it during his audition video and during the season, explaining that he both can't see some colors and perceives others differently and has both red-green and blue-yellow colorblindness. Also qualifies as Deaf Composer since the judges would frequently laud his color choices on garments and acknowledge that they weren't sure how they looked to him but they found them praiseworthy. On a few occasions he's also shown consulting with other designers about whether two colors match and/or look good together.
- In the Psych episode "Santabarbaratown", Shawn has a Eureka Moment when he remembers that Thea Summers is color blind, which helps prove that her father was Ellis Beaumont, who was recently murdered and had the condition as well. The mechanism of inheritance is also oversimplified by a stating that a color blind man must have a color blind daughter, when in reality she would have to get the gene from both parents due to it being carried on the X chromosome in order for it to be expressed.
- Inverted in The X-Files episode "Wetwired", where Mulder's red-green color blindness turns into an unexpected asset, as The Government's subliminal messages operate primarily in that spectrum, and he is thus the only one immune to them.
- On Elementary, an episode opens with the rare bit of Gregson and Bell, not Holmes and Watson, busting a crook. They confront a man who killed a woman for ending their affair. They note how the man is color blind and when he realized he couldn't clean up all the blood from the shooting, he just covered it with new wallpaper. But because of his color blindness, he failed to realize the shade of the pattern was slightly different than the original which stuck out like a sore thumb to the cops and allowed them to find the blood and bullet hole.
- In The Goon Show episode "Foiled by President Fred", Eccles has a red sack of forged money and a blue sack of genuine money. Or maybe it's the other way around. Thanks to his colour blindness, he isn't able to tell which sack is which colour anyway...
- This forms a part of a Moon Logic Puzzle in Edna & Harvey: Harveys New Eyes where a pizza's toppings must be made in accordance with the wishes of the characters, the catch being that all are different types of color blind. Adrian has red/yellow color blindness, Peter has red/green color blindness, Petra has yellow/green color blindness, and Drogglejug has green/blue color blindness.
- Valkyria Chronicles II combines this with Art Major Biology by having one character, The Medic Cosette becoming colorblind after witnessing their parent's death, making them unable to see the color red. They, naturally, get faced with a Wire Dilemma and not only overcome it but are cured of their color blindness in the process. Needless to say while color blindness can sometimes be caused by factors other than genetics (usually physical trauma to the brain or retina) witnessing a traumatic incident isn't one of them, and Epiphany Therapy isn't known to cure it.
- Played for Drama in Higurashi: When They Cry where Satoko and Satoshi Hojo are both color blind and cannot tell broccoli from cauliflower as a result, which results in a scene where Big Bad Miyo Takano asks Satoko which of the two is green while pointing a gun at her head, and after panicking Satoko picks at random. She's correct, but Takano shoots her dead anyway.
- In Phoenix Wright: Ace Attorney: Trials & Tribulations, Prosecutor Godot is blind-blind, and requires a large electronic Cyclops-like visor to see anything at all. But, much like Cyclops himself, the red lenses tint everything red, making it impossible for him to see red against a white background. This is originally Played for Laughs when he fails to notice a comically large "bloodstain" on an apron (it was just ketchup), but it ends up being Chekhov's Gag later.
- In Another Gaming Comic everyone's hair started out shaded green due to the author being colorblind. He eventually changed it so everyone has more standard hair colors.
- In Freefall Florence, an Uplifted wolf, is color blind.
- One Nodwick comic had the party detailing this time they'd heard a red dragon was terrorizing a village and bought an "Orb of Commanding Red Dragons" to vanquish it, only to find that the village in question had a tendency towards genetic red-green color blindness.
- Once in Schlock Mercenary Lieutenant Pi attempted to disarm some rogue ordnance by pressing the green button on his remote, and not the red detonation button. Cut to his head in a jar saying "Nobody told me I was red-green colorblind."
- In Sorcery 101, werewolves become color blind, much to the dismay of Brad, who prior to his transformation was a graphic designer.
- In Widdershins, Jack O'Malley sees spirits in color, but the rest of the world in shades of grey. So he has no reference point for which words go with which colors, and when they go through a power-swap storyline he has to use descriptions like "it's the same color as that thing" instead of "it's green."
- In Red vs. Blue, this turns out to be the reason Sister ended up on the Blue Team, since she was trying to go to the Red Team to be with her brother Grif but her disability combined with her general stupidity meant she joined the wrong army by accident.
- Played for Laughs in the Door Monster sketch Can't See Green, where green objects are invisible to a character with red-green colorblindess.
- Ray Gillette in Archer is implied to be red-green color blind, which is something of a problem as he's ISIS' demolitions expert (though it's possible he was just Trolling Archer by intentionally hitting the wrong buttons in an elevator). If true, then by extension he likely lied in order to get his aircraft piloting license.
- In the Family Guy episode "Brian Writes A Bestseller", Brian complains during a particularly prima-donna moment that all the M&Ms brought to him are gray when he specifically said to remove them, the joke being that, as a dog, they're all going to look that way to him.
- In Littlest Pet Shop (2012) Zoe mentions in the episode "The Hedgehog In The Plastic Bubble" that dogs cannot see red as a Furry Reminder.
- In the Martha Speaks episode, "Martha the Witness", Martha represents Mrs. Demson as the witness to a traffic accident that destroyed her lawn furniture. At one point, the defendant's lawyer shows Martha three cards; two red and one green. Martha, however, is unable to tell the three cards apart, due to her being colorblind, but towards the end of the episode, she reveals that she is able to tell that the top of a traffic light is always red, and the bottom of the traffic light is always green.
- In the Sonic Boom episode "Bro-Down Showdown", Sonic and Knuckles compete on the titular game show to win a new couch for Amy after they spill nachos on her old one. Sonic is teamed up with Dr. Eggman, and Knuckles is teamed up with Mike the Ox. At one point, Comedy Chimp asks Mike what color Knuckles is. Due to being colorblind, Mike guesses green, even though Knuckles is red. When he finds out he answered wrong, he admits he's colorblind, and when a red light flashes, he asks if the light was green.
- In All Dogs Go to Heaven, while Itchy is busting Charlie out of jail, Charlie warns Itchy not to break through a pipe because it could be a water main. Itchy insists that it can't be: water mains are green, and this pipe is red. Charlie retorts that Itchy has always been colorblind. Not helped by continuity error that comes literally a second later, when Itchy insists that the pipe is green and water mains are red.
- In the Adventure Time episode "Red Starved", several characters proclaim that the large gem Finn discovers is a green emerald, even though he and the audience can clearly see it is a red ruby. Eventually, Finn gets fed up and describes it as a perfectly normal, dark gray ruby. Jake then tells Finn he's color-blind, at which point the audience sees the gem as an emerald as well.