Unfortunately, it's impossible to predict with certainty what a child's eye color will be. In fact, scientists still don't have a way to accurately guess eye color since there are up to sixteen different genes that could be responsible for helping to determine eye color.
Though scientists used to believe that it was a relatively simple case of blue eyes being a recessive gene, and brown eyes being a dominant gene, it's now been found that eye color is determined by as many as 16 different genes. In fact, almost any combinations of parent-child eye color can occur. In general, darker colors tend to dominate lighter colors.
That said, we do know that the main genes found to determine eye color are OCA2 and HERC2. There is a fun tool that you can use to try to guess your future baby's eye color based on your eyes, your siblings' eyes, and your parents eyes.
Here's the eye-color calculator if you want to give it a try!
This is a good example of heterochromia.
Other Color Variations
There are other variations that can occur in eye color aside from basic color. As you've learned, the iris is a complicated place! Its color comes from the combined effect of texture, pigmentation, fibrous tissue and blood vessels within the iris and stroma. Here are some other eye variations that can occur.
Heterochromia
This is where one eye is differently colored from another one, or one iris has different colors in it. Kate Bosworth is a good example of this. This results from uneven melanin content.
If you look closely, you'll see that many eyes have a limbal ring around the iris.
Limbal Ring
A limbal ring is a dark ring around the iris of an eye. Since they fade with age, they usually signify youth and are considered attractive.