The color of our eyes is determined by the amount and distribution of pigments in the iris, which is the colored part that surrounds the pupil. Melanin and lipochrome are the two pigments that determine eye color, with melanin being a brown-black pigment and lipochrome being a yellowish pigment. The level of melanin and lipochrome in the iris is what determines the color of the eyes.
Black eyes appear very dark, almost black, and are usually found in individuals with a lot of melanin in their iris. However, it is important to note that the color of the eyes does not change in different lighting conditions, including sunlight. Although the perception of eye color may vary based on lighting conditions, this is not an actual change in the color of the eyes. For example, individuals with hazel eyes may appear more green in bright sunlight and more brown in dim lighting due to the way light reflects off the iris and the surrounding environment.
There are some rare medical conditions that can cause a gradual change in eye color over time, but these changes are not immediate nor occur in response to sunlight. Horner’s syndrome is one such condition that can cause one eye to appear lighter in color due to nerve damage that controls the pupil and iris. Pigmentary glaucoma can cause a gradual darkening of the iris over time.
In conclusion, the color of our eyes is determined by the amount and distribution of pigments in the iris and does not change in response to sunlight or different lighting conditions. Although the perception of eye color may vary based on lighting, it is not an actual change in eye color. Rare medical conditions can cause a gradual change in eye color, but this is not an immediate response to sunlight.