The Eye is like a camera because of its structures that function similar to those of a camera. The Cornea acts as the camera lens, the Iris acts like the diaphragm of a camera, the Crystalline lens functions like an auto focus camera lens, and the Retina is like the electronic image sensor or the film of a camera.
ANATOMY OF THE EYE:
- Cornea – is a transparent protective covering of the eye. It is where the focusing of light primarily occurs. Cornea allows you to see around you just like the camera lens.
- Iris – is the thin, circular colored structure, and the most visible part of the eye. It functions like the diaphragm of a camera. The iris controls the amount of light reaching the back of the eye, the retina, by adjusting the size of the pupil (aperture). The color of the iris is what is referred to as the eye color.
- Crystalline Lens – The lens is a transparent layer located at the back of the pupil that helps to focus light along with the retina. It changes its shape to adjust the focusing distance of the eye in order to get a good image of an object. This adjustment of the lens is called accommodation, which is similar to the auto focus of a camera lens.
- Retina – The retina is the innermost, light-sensitive layer of the eye. It functions like the film in a camera. It is consists of nerve tissues which sense the light that enters the eye. The Retina converts the light rays it receives from the lens into signals, and sends these signals to the brain via the optic nerves, which are then converted into visual images
Retina has 2 photoreceptors cells, named rods and cones. The rods are used in peripheral vision and are more sensitive than cone cells. The rods are responsible for our dark and night vision. The cones, on the other hand, provide the eye’s color sensitivity. They are less sensitive to light than the rods. They are used for daytime vision. - Macula – is a small, yellowish, and highly sensitive section of the retina. It is found in the center of the retina. It provides us the clearest and most detailed vision. The center of the macula is called the fovea , this tiny area is responsible for our sharpest vision.
- Optic Nerve or the cranial nerve II – like a wire that connects the eye to the brain. It transmits the impulses from the retina to the brain, which interprets them as visual images.
- Pupil – is the round, black circle in the center of the iris of the eye. It allows in and regulates the amount of light that enters the retina by adjusting its size (which is controlled by iris).
- Conjunctiva – The conjunctiva is a mucus layer that helps lubricate the eye. It also produces tears, (smaller amount of tears than that of lacrimal sacs) to help moisten the eye. It lines the inside of the eyelids. Infections to this area are known as “Pink Eye.”
- Sclera – The Sclera is the outer white part of the eye. It provides protection and structure for the inner sensitive parts of the eye.
- Lacrimal Sac – which drain tears from the eye’s surface.
- Lacrimal Glands – is a gland that produces the majority of the tears. Tears are produced to protect and lubricate the eye.
- Choroid – vascular and thickest layer of the eye. It is located between the retina and the sclera. The function of the Choroid is to nourish the retina with oxygen and nutrients.
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