Why are there different colors in eyeballs?

The different colors of eyeballs, primarily seen in the iris, are due to variations in pigmentation and the structure of the eye. The color is mainly determined by the amount and type of melanin present; higher melanin levels result in brown eyes, while lower levels can lead to blue or green eyes. Additionally, the scattering of light by the eye's structures can influence perceived eye color. Genetic factors play a significant role in determining an individual's eye color.