If a baby was born with greyish blue eyes you might be surprised later. The secret of blue eyes, which is also called “the sky effect,” is in the low content of melanin in irises that disperses light and reveals an even brighter, blue-like color. The eye color of many babies at the age of 3-18 months can become darker if the quantity of melanocytes in their irises becomes bigger. For example, people who live in mountainous regions are often born with blue eyes that transform into hazel eyes later but it mostly depends on their parents’ eye color. Sometimes, the final eye color isn’t established until the age of 12.