People can trace their genetic modification back to a single ancestor.

Our eyes contain some very interesting facts about ourselves and our biological makeup.

BY R.J. WILSON

The old adage is that the eyes are the windows to the soul. While this may or may not be true, one thing is for certain—your eyes can also reveal certain facts about your specific biology. You won't believe your eyes once you read the following surprising facts.

1. All blue-eyed people share a common ancestor.

Blue eyes are very rare, found only in people with a northern European background. But it might surprise you to learn that these eyes can be traced back to an even more specific region. In fact, the blue-eyed guys and gals of the world owe their unique eyes to a single person.

When humans first evolved, everyone had brown eyes. That all changed due to a mutation in the OCA2 gene, which led to less melanin production in the iris. This specific mutation would have occurred between 6,000 and 10,000 years ago somewhere in the Baltic Sea region. This person would then pass down that trait to millions of people.

2. Certain eye colors are prone to cataracts.

Cataracts occur when the lens of the eyes develop a clouding that impacts vision. It's comparable to looking through a foggy piece of glass. Some people are more susceptible to developing cataracts than others.

Those with lighter eyes tend to be more prone to developing cataracts, maybe even two and a half times more likely. Researchers believe that people with lighter eyes have less protection from sunlight which can eventually lead to vision problems. However, this claim requires further research as the results are not entirely certain.

3. Cataracts actually aren't caused by any disease.

Some people might think that cataracts are caused by a virus, bacteria, or other health issues. However, they're actually caused by aging.

As we age, proteins clump together and harden, clouding our vision and eventually leading to significant vision impairment and potentially blindness. The only way to treat cataracts is to remove them from the eye through a surgical procedure.

4. Brown-eyed people may have faster reaction times.

Researchers have actually tested the reaction times in dark-eyed people versus light-eyed people and found that there actually is a difference. Those with brown eyes performed the best when it came to reacting quickly.

While brown-eyed people had better immediate reactions, those with blue eyes did better on other tests. Blue-eyed people were better at complex tasks like game theory. The differences aren't major, but they are definitely there.

5. The cornea is actually without blood vessels.

Our corneas are unique in that they don't contain blood vessels. In fact, that's the only place in our body that doesn't get blood. The cornea receives its nutrients from tear ducts and from the aqueous humor.

This is actually an evolutionary trait to ensure we have perfect vision. If we had blood vessels in the cornea, they would obscure our otherwise perfect vision.

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