The Golden Eagle

     We’ve covered every external part of the eye, so lets start with the parts that are inside. First is the aqueous humor which is both in front and behind the iris. The aqueous humor is a liquid whose job is to nourish the cornea and the lens. The lens is directly behind the iris. Its job is to continue to focus the light. “The cornea focuses most of the light, then it passes through the lens, which continues to focus the light (Former qtd. in Than).” The ciliary muscles (also called ciliary body) hold the lens in place. These muscles also change the shape of the lens which affects how far we can see.  To see far, the muscles make the lens flat and to see something near the muscles make the lens thicker. When light is focused through the lens, it goes through the vitreous humor. The vitreous humor keeps the shape of our eye. Without it, our eye would be flat! Once light has gone through the vitreous humor, it hits the retina. The retina is made up of two different kinds of photoreceptors, rods and cones. Rods see very little detail but can see movement and contrast. They are also responsible for seeing in dim light. Cones see detail and color. Rods are much more numerous than cones in the human eye. Almost all the cone in the human eye are found in a place called the macula. Inside the macula is the fovea, which has only cones. This mean that when light hits the fovea, a much more detailed image can be formed, while light hitting the retina farther away from the fovea doesn’t make as detailed of an image. The photoreceptors catch the light and transform it into electrical signals. These signals are then sent to the optic nerve which take the information to the brain to process the image.