Here are 18 causes of red eye, from pink eye to glaucoma. Having red eyes is something that can happen to any of us. These colors occur naturally in nature and are on the light spectrum, so no color combine to make blue. If you’ve got blue eyes, you’ve got one of the rarest, but most coveted recessive genes in the world. How common is it for someone to have red hair and blue eyes?
How common is it for someone to have red hair and blue eyes? How true are those rumors: Webmd tells you what's behind your bloodshot eyes and how to get the red out. But sunlight contains more than just uv light. Often it's not serious, but sometimes, a red eye is a red flag. In fact, only about 17 percent of the world’s population has blue eyes. In contrast, more than 50 percent of the global population is be. The three primary colors are red, blue, and yellow.