What is the significance of Loki's eyes changing color in many myths?

Question

So far I’ve found three references to Loki’s eyes changing color. In “The Theft of Idun’s Apples” Loki’s eyes “gleamed red and green.” When Odin points out that Loki could have broken his promise to the eagle/giant. In “The Treasures of the Gods” Loki’s again “flicker red and green” as he watches the dwarfs make Sif’s replacement hair. Finally in “Thor’s Journey to Utgard” Loki’s eyes gleam “now brown, now green, now indigo.” when he convinces Thor to let him come. Furthermore no other god’s eyes are described as changing color, not even Odin who is also a shape shifter.

Answer 1

Loki is an adept shape-shifter, with the ability to change both form (examples include transmogrification to a salmon, horse, bird, flea, etc.) and sex.

As a result, his eyes would change colour as well.