Parts of the eye are essential components of the human visual system. Uveas (5 letters) is a layer of the eye that contains blood vessels, muscles, and connective tissue. Iris (6 letters) is the colored part of the eye that controls the amount of light entering the eye. Retinae (7 letters) is the light-sensitive layer of tissue at the back of the eye that receives images and sends them to the brain. Together, these parts of the eye work together to enable us to see.