It seems that you are very interested in this particular field right ? So, as far as we know, people have different colored eyes ever from birth due to difference races, as well as their genes. That is formed thousands of years ago and it would not change for now. The color of our eyes are mainly decided by the types of the genes and the configuration of them. So, it would not be uncommon for you to see this thing.
Well, actually people have different eye colors. So you should know the reasons about it. Generally speaking, the pupil which is the black spot in the middle of your eye will allow light to enter the eye. It is a hole. And around this hole is the colored part of the eye, which is named as the iris. For iris which has pigment, it regulates the size of the pupil and how much light is allowed into the eye. So we can say that the iris give the eye its color because of the pigment. If there are large amount of pigment present, the color of the eye would be black, brown or hazel. Of course, small amounts would result in light green or light blue eyes. that why people have different colors.
There are several reasons can contribute to different eye color, so let me name a few. First the reason is Pigmentation, which means the iris contains the colored pigment that determines a person's eye color. Many babies' eyes change color as they grow older. It is common for a baby's blue eyes to change to brown in about a 3-year period as the brown pigment (known as melanin) becomes present later in life. It is uncommon for melanin to be present in newborns.
And another reason is most commonly know as Genetics, The formation of eye color is a complex, scientific issue that involves multiple possibilities of combinations of genes received from both parents.
So as you can see the area you born and the ancestors of you may decide your eye color.