I'm not sure if you know anything about Japanese folklore but, from ancient Japanese myth and religion of Shinito, Amaterasu, Tsukuyomi, and Susanoo were all gods. When Inzanagi washed his face after escaping the underworld his left eye became the sun goddess, Amaterasu. I think Kishimoto only made Sasuke's and Sasuke's eye alone that way as a meaning that he may become the greatest of the Uchiha. Just as Inzanagi along with his sister wife Inzanami was the greatest of his family. Ohh and you should check out all the folklore on Wikipedia it's oretty interesting Amaterasu is the sun goddess, which is why Amaterasu releases flames that burn till nothing's left. Susanoo is the god of the sea and raging storms. Tsukuyomi is the moon god. It's pretty interesting
how each gods attribute ties into each of the Uchiha technique.