Note: As requested by Salila Glacerious. This one gave me a fair bit of trouble, so I took a few creative/humorous liberties. Apologies if it's not as well-rounded as the others. Oh, and I mean no offence to anyone that wears glasses.
Warnings: None
Pairings: None
Characters: Itachi, Fugaku Uchiha
Once upon a time, many ninja, aggrieved by the guidelines of the ninja lifestyle, pointed to the Uchiha clan as the source of all the uptight, carved-in-stone rules that may once have been practical, but inevitably became excessively stretched out and obsessively followed. These rules dehumanized the ninja, and made them the emotionless tools of war that were so desirable on the battlefield, but so crippled as people.
The Uchiha clan had an intense focus on being the elite clan, with ninja of the highest caliber in any realm of battle study. These three rules of the Uchiha clan were believed to be the only way to be the best, the crème de la crème of the ninja world. These rules are basically all the same, and in short are summarized into the Golden Rule of Elite Ninja: Ninja must never have personalities; they must never be human:
1. Ninja must never show (or have) emotions, lest it gets in the way of the mission
2. Ninja must never show (or have) habits, lest they get read and used by opponents
3. Ninja must never show (or have) weakness, lest they be exploited by enemies
In the Uchiha clan, children began receiving formal battle training at the age of three. Any outward show of desires or feelings were expected to be conscious and calculated displays, perhaps used to mislead an opponent or politely ask for another serving of ice cream. The children of the clan head were discouraged from showing any signs of weakness or emotions after the age of two; they were essentially expected to be the miniature role-models of the ideal ninja.
As the eldest son of the clan head, Itachi Uchiha was no different.
However, Itachi Uchiha had a serious problem with one rule in particular.
It's all well and good for ninja to never show weaknesses, when they are a member of the Uchiha clan - and by definition, don't have any weaknesses (as far as the clan elders are concerned) - but when an Uchiha - an Uchiha prodigy, nonetheless - is faced with difficulties fulfilling rule #3, the clan head, Fugaku, didn't know what to do about his son.
It was a very simple problem; Itachi didn't have 20/20 vision.
His vision wasn't even that bad, and he could easily hit moving bulls-eye targets from twenty-five paces away, and for a long time, nobody in the Uchiha clan knew anything about their clan heir except that he was fast on his feet and surprisingly good with kunai, even for an Uchiha child his age.
But when Itachi was six years old and enrolled in the local ninja academy, he had his eyesight tested, as part of a standard health examination. The examiner noticed that Itachi squinted his eyes just slightly when he tried to read the poster on the far side of the hallway. Itachi didn't furrow his eyebrows or crinkle the corners of his eyes the way most others would when squinting, but instead, the skin below his lower eyelids would pinch up a little, and the small wrinkles on his face would grow slightly more prominent for a single heartbeat.
When the examiner suggested to Fugaku that Itachi get eyeglasses, the clan head nearly sent a fireball to torch the man into ashes right then and there.
There is, after all, another overarching rule in the Uchiha clan, arguably even more important than the Golden Rule of Elite Ninja. This subtle rule was never spoken aloud, but permeated everything that the Uchiha said and did on a day-to-day basis, both during and outside of missions.
(The Uspoken All-Important Uchiha Code of Conduct Rule; Otherwise Known as the Rule of Three C's: Uchihas must act Calm, Collected, and above all, Cool)
It was the general belief among the Uchiha clan that glasses were not cool. Glasses were a blatant sign of a crippling weakness: sub-par eyesight. Glasses flashed in the sun and gave away positions to enemies. Glasses detracted from the perfection of an Uchiha's facial structure.
That was feeling the Uchiha clan held about glasses. However, the actual, practical reason for all this anti-glasses sentiment among the Uchiha clan was this: When a sharingan is refracted through the lenses of a pair of eyeglasses (or some sort of glass lens)... well... suffice to say that some pretty embarrassing and/or weird things tend to happen. The sharingan would essentially spin out of control and concoct all kinds of psychedelic genjutsu that affected not only the victim, but sometimes even the caster of the jutsu. There was the little-known legend of Madara Uchiha's twice-inverted, optic-tango telescope-incident, but that was sealed deep in the secret files of the Uchiha complex, and anyway, it all boiled down to this:
The Uchiha cultivated a contempt and hatred for glasses in order to protect their sense pride and hide this weakness from the world, which all boiled down to this:
Glasses for Itachi were out of the question.
And so, as his eyesight continued to go downhill, Itachi perfected a way of squinting that was unnoticeable to his allies and opponents.
And the lines under his eyes continued to become more prominent as time wore on.