Solid Snake, real name David, also known as Old Snake, and briefly known as Iroquois Pliskin, or simply Snake, is a former spy, special operations soldier, and mercenary. Possessing an IQ of 180 and fluent in six languages, [3][5] the fame he achieved from his military exploits earned him such monikers as "Legendary Soldier," [3] "Legendary Hero," [6] and "the Man Who Makes the Impossible. Ironically, liquids eyes are the only other character that seems to be in question.
According to the fandom wiki, it says blue, and cites this "Metal Gear Solid V: The Phantom Pain, Kojima Productions (2015). Yoji Shinkawa's artwork for the original Metal Gear Solid previously depicted Liquid's eye color as green.". For Metal Gear Solid 3: Subsistence on the PlayStation 2, a GameFAQs message board topic titled "What is Snake's eye color?".
Solid Snake has green eyes. Metal Gear Solid 4 this is between game development of his appearances of Big Boss in MGS3 and MGS: PW. Solid Snake has blue eyes in MG1, MG2, MGS4.
I only think they were "green" in MGS2, but I'm not sure. Eye color also changes appearance with lighting conditions, so that's something to consider. It's possible Big Boss's single eye in MGS4 is not his own, given that his body was rebuilt (maybe not Solidus's or Liquid's, but that's speculation).
Another consideration is that they gave a lighter. Are Venom Snake's eyes and Naked Snake's eyes the same color? So I was watching a few Metal Gear Solid V videos, and when I saw the scene where Volgin discovered that Venom Snake wasn't Big Boss I wondered how he noticed, was it because of the eye colors? In MGS3 it is said that Naked Snake's eyes are blue, but Venom's look more green to me. Snake, also known as Big Boss or Naked Snake in the Metal Gear Solid series, lost his eye during a mission in the 1960s.
He was injured in an explosion, which resulted in the loss of his left eye. The Solid Eye System was an optoelectronic device invented by Otacon (with the help of Sunny) resembling an eye patch. It was used by Solid Snake in his final mission to eliminate Liquid Ocelot.
See also: Liquid Sun, Solid Sun, Third Sun, Twin Suns, Old Sun, and Naked Sin/Naked Son The Solid Eye appeared similar to a plastic eye patch, with text of the device name and serial number printed on. According to this link a snake's eye color change right before they shed their skin. Their eyes change to a milky blue or a blue-grey eye color and then they shed their skins.
Old Snake having blue-grey eyes might show that he is on the verge of change or death. Either it's very clever fridge brilliance or just a coincidence. I just think it's.
For his appearance in Metal Gear Solid 4: Guns of the Patriots, see Old Snake Pale Caucasian 32-36 years old 5'11 (182 cm) Brown mullet Muscular build Blue eyes 165 pounds (75 kg) Light goatee (MGS2) Grey skin.