The main difference in eye shape is the way the upper eyelid meets the inner corner of the eye. In many ethnicities, including East Asians, Southeast Asians, Polynesians and Native Americans, there is commonly a slight fold at this point, called an ‘epicanthic fold’.
This is caused by fat deposits under the skin, and one theory is that it evolved to protect the eye against the cold, or against the stronger ultraviolet light found in snowy and desert environments.
- Why do our eyes come in different colours?
- Why are noses always in between eyes?
- How can one eye alone provide depth perception?
- Is human eyesight getting worse?