Why do orientals have 'slanted' eyes?
What evolutionary purpose do they have?
Some say it is because it served a purpose in cold environments, like in the Tibetan mountains. Of course, this reasoning seems to fail considering the cold environments that Nordic people have also endured.
You do have to remember that you ascribing purpose-driven traits to something that is supposed to not have any meaning or purpose at all.
Slanted eyes on Asians (Oriental is not a people, its a style derived from what is commonly known as "Asians") is nothing more than more fatty tissue around the ocular cavity than other people. It likely started as mutation in a few people that later fixed itself through procreation. Now lots of people have the trait.
There probably is no grand reason. It may have just happened quite incidentally.
“I know where I am and who I am. I'm on the brink of disillusionment, on the eve of bitter sweet. I'm perpetually one step away from either collapse or rebirth. I am exactly where I need to be. Either way I go towards rebirth, for a total collapse often brings a rebirth." -Andrew Jaramillo