Eye color statistics in the U.S.
Brown - 45%
Blue and blue-grey - 27%
Hazel - 18%
Green - 9%
Other - 1%
There is a slight difference in visual acuity comparing light and dark colored eyes. Lighter eyes, such as blue or green eyes, have less pigment in the iris, which leaves the iris more translucent and lets more light into the eye. This means that light-eyed people tend to have slightly better night vision than dark-eyed people.
However, darker eyes act like a stronger filter for light, which means that dark-eyed people tend to see better in bright sunlight and are less susceptible to glare.