Eye color is largely determined by the amount of melanin we have in our irises. Melanin is also what gives our hair and skin its hue. Brown is the most common eye color in the world, while green is the least common. Did you know that much like our skin's undertone, our eye color doesn't change as we age (unless of course we develop certain health conditions that alter its hue)?

Just like a sunburn can tell you about your skin's undertone, so can the color of your eyes, although it can't be the sole or final determinant. Makeup artist Robert Sesnek told Byrdie, "Eye and hair color can have any skin undertone in it, but as a generalization, deeper skin tones and deeper eye color usually tend to have warmer undertones while very fair skin and lighter eyes tend to have neutral or cool undertones." 

So if you've got green, golden-brown, hazel, or amber-hued eyes, you likely have a warm undertone, and if you have blue, dark brown, or gray-colored eyes, this could mean a cooler undertone. Determining your skin's undertone based on just your eye color is probably not a good idea though, so try doing all other recommended tests if you want to arrive at a more conclusive result.