Glasses are universally seen as a sign of intelligence, but in anime it's the shape of the frames that's telling of the personality. Generally speaking, characters with rectangular or square frames tend to have "harsher" personalities that range from emotionally distant to downright evil. Characters with the circular frames (they can be ovals or perfect circles, depending on how serious the work is) have more "soft" personalities that range from comically nerdy to shy and sweet.

This trope could possibly be an extension of TsurimeEyes and TaremeEyes, as characters with Tsurime Eyes eyes will generally wear square frames while someone with Tareme Eyes will usually opt for round frames.

!!Related tropes:

* BespectacledBastardBoyfriend
* CoolShades
* EyeGlasses
* FourEyesZeroSoul
* HotLibrarian
* MadScientist: Depending on whether he's a lovable {{cloudcuckoolander}} or a villain.
* MakingASpectacleOfYourself
* {{Meganekko}}
* NerdGlasses
* OpaqueLenses
* PurelyAestheticGlasses
* ScaryShinyGlasses
* SexySpectacles
* TheShortGuyWithGlasses
* SinisterShades
* StoicSpectacles


[[folder:Anime & Manga]]
* Gendo Ikari from ''Anime/NeonGenesisEvangelion'' has somewhat rectangular frames but they are rounded at the ends. Sometimes, the light reflects off them enough to hide his eyes, cluing the audience in to his inhumane nature.
* ''Manga/{{Bleach}}'' seems to love this trope. You can pretty much tell a character's alliance or personality based on the shape of their glasses:
** Uryuu Ishida, while not a villain, is the hero's former rival and antagonist. Is very reserved, and depending on the person, rather cold.
*** Ishida's father wears almost rectangular glasses, but is even more emotionally distant than his son.
** Tessai Tsukabishi is rather stoic and intimidating, so his rectangular glasses suit him perfectly.
** Ironically, in Aizen's case, the rectangular glasses were part of his "nice guy" facade and he ditches them once he outs himself as the story's BigBad. Perhaps he couldn't quite hide his evilness as well as he thought...
** Szayel Aporro Granz is a sadistic MadScientist who wears hipster glasses.
** For round glasses we have Nanaos Ise, a comically uptight SugarAndIcePersonality who is staunchly good.
** Nanao's predecessor Risa Yadomaru also sports round glasses, perhaps to purposely invoke the meganekko look since she also wears a school uniform.
** Then we have Chizuru, who has ''triangle'' shaped glasses, probably to reflect her rather...eccentric personality.
* Shirai-sensei from ''Kodomo no Jikan'' is quite the SternTeacher, but her actual personality isn't anywhere near as harsh as it first appears and she wears the oval type glasses. Mimi is shy and naturally her glasses are the circular type.
* ''[[Manga/AxisPowersHetalia Hetalia]]'':
** The countries, America and Canada, have this as one of their differentiating features (not that anyone notices). Canada is shy and nice so he wears circular frames while America is abrasive and somewhat arrogant so he wears square frames.
** Austria's frames are square with rounded edges since he's a SugarAndIcePersonality.
** Estonia's are square with rounded edges since he's generally a NiceGuy / OnlySaneMan.
** Cameroon and Sweden's glasses are square framed since they're both StoicSpectacles.
** Thailand has circular frames since he's cheerful and fun loving.
* ''Manga/{{Saiyuki}}'' has an interesting example, in that [[{{Yandere}} Cho Gonou]] is shown with square glasses, while [[ThatManIsDead Cho]] [[MeaningfulRename Hakkai]] has a single round [[HighClassGlass monocle]] instead.
* Lampshaded in ''Manga/SlamDunk'', [[TeamMom Kogure]] wears circular glasses while [[FourEyesZeroSoul Hanagata]] wears square ones.
* Barnaby from ''Anime/TigerAndBunny'' wears hexagonal glasses (which can be seen as something of a cross between rectangular and circular lenses) and starts the series as both a StoicSpectacles with {{Tsurime}} and a SugarAndIcePersonality who sometimes treads into {{Tsundere}} territory. He does, however, [[DefrostingIceKing change quite a bit as the series progresses.]]
* Father Alexander Anderson from ''Anime/{{Hellsing}}'' wears perfectly round glasses and is shown to be a gentle and rather amiable man. But in battle, his glasses immediately turn an opaque blue and he sports a seemingly constant SlasherSmile. Alucard himself sports a SlasherSmile and round glasses, but is an amoral vampire willing to take out an army of {{Mooks}} without hesitation.
* Prince of Tennis has the following:
** Tezuka has oval frames, denoting his SugarAndIcePersonality.
** Inui has rectangular OpaqueLenses because he is a BadassBookworm, and they turn into ScaryShinyGlasses whenever [[GargleBlaster his Inui Juices]] make an appearance.
** Oshitari has round glasses and a fondness for the romance genre.
** Konjiki Koharu also has oval glasses; while he's usually fun-loving and goofy, he's also a super genius data tennis player who managed to analyse Momo's and Kaidoh's play styles right away.
** Kite Eishirou has rectangular glasses and is known as the Hitman because of his tendency to cheat and use violence.
* Yagyuu Hiroshi has oval lenses. While ruthless on the court (even against his own partner when they were forced to play against each other), he's pretty nice when not playing tennis.
* Weevil Underwood/Insector Haga of ''Anime/YuGiOh'' is a bit of an interesting case. Despite having very narrow, creepy-looking, {{Tsurime}} eyes and having a pretty {{Jerkass}} SmugSnake personality, both sets of glasses he wears are very rounded. This may have been intentionally done to make him look more [[AnimalMotif insect-like]].
* Els Tasmin of ''Manga/MagicalGirlLyricalNanohaVivid'' has horizontal, oval frames. While she tries her hardest to be the stern and serious type of character, her personality is closer to comical ButtMonkey.

[[folder:Comic Books]]
* Clark Kent's Nerd Glasses are horn rimmed and not quite rectangular, the closest you can get to the "round=nerdy" part of this trope realistically.
* In ''ComicBook/KingdomCome'', Edward Nigma (aka the Riddler) wears round bifocals that scarecly resemble question marks which fit his nerdy personality and alludes to his former life of crime.

[[folder:Film (Live Action)]]
* ''Film/TheMatrix''. Inside the simulation, the humans wear oval shades, while the Agents wear rectangular ones. In the sequels, as Neo and Smith become NotSoDifferent, Neo's shades become more angular and Smith's become more rounded.

[[folder:Video Games]]
* In the visual novel ''VisualNovel/KatawaShoujo'', the intelligent, aggressive Student Council President wears rectangle frames. In contrast, the shy librarian Yuuko had oval shaped lenses (until her recent, more realistic re-design).