![]() ![]() The retina receives light and sends electrical impulses to the brain that result in sight. The light sensitive retina consists of four major layers: the outer neural layer, containing nerve cells and blood vessels the photoreceptor layer, a single layer that contains the light sensing rods and cones the retinal pigment epithelium (RPE) and the choroid, consisting of connective tissue and capillaries. ![]() It is composed of millions of visual cells and it is connected by the optic nerve to the brain. RetinaĪ thin multi-layered membrane which lines the inside back two-thirds of the eye. It focuses light rays entering through the pupil in order to form an image on the retina. LensĪ transparent biconvex structure located behind the iris. Its color varies from pale blue to dark brown. The pigmented (colored) membrane of the eye, the iris is located between the cornea and the lens. The size of the pupil changes automatically to control the amount of light entering the eye. The round black hole in the center of the iris. The cornea is an important part of the focusing system of the eye. It is a thick, nearly circular structure covering the lens. Glasses, contact lenses, and artificial lenses all help us to see more clearly.The transparent “front window” of the eye. The lens of the eye helps us to focus but sometimes needs some additional help in order to focus clearly. The lens of a camera is able to focus on objects far away and up close with the help of mirrors and other mechanical devices. When it is very dark, our pupils are very large, letting in more light. The iris and the pupil control how much light to let into the back of the eye. The eye, like the camera shutter, operates in the same way. The shutter of a camera can close or open depending upon the amount of light needed to expose the film in the back of the camera. The cells in the retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve and then to the brain. The cornea and the lens help to focus the light rays onto the back of the eye (retina). Light passes through the front of the eye (cornea) to the lens. How we see depends upon the transfer of light. The eye is connected to the brain and dependent upon the brain to interpret what we see. Sight, like the other senses is closely related to other parts of our anatomy. The five senses include sight, sound, taste, hearing and touch. The, clear, gelatinous substance filling the central cavity of the eye. The white outer coat of the eye, surrounding the iris. The retina senses light and creates electrical impulses that are sent through the optic nerve to the brain. The nerve layer lining the back of the eye. This opening and closing of light into the eye is much like the aperture in most 35 mm cameras which lets in more or less light depending upon the conditions. The pupil changes size to adjust for the amount of light available (smaller for bright light and larger for low light). The dark center opening in the middle of the iris. Glaucoma is one of the most common eye conditions related to optic nerve damage. This reversal of the images that we see is much like a mirror in a camera. The retina sees images upside down but the brain turns images right side up. (In order to see, we must have light and our eyes must be connected to the brain.) Your brain actually controls what you see, since it combines images. ![]() The deterioration of the macula is a common condition as we get older (age related macular degeneration or ARMD).Ī bundle of more than a million nerve fibers carrying visual messages from the retina to the brain. In the macula these light-sensitive cells allow us to see fine details clearly in the center of our visual field. The area in the retina that contains special light-sensitive cells. Intraocular lenses are used to replace lenses clouded by cataracts. Our lens deteriorates as we age, resulting in the need for reading glasses. The lens is transparent, and can be replaced if necessary. And when there is low light, the iris opens up the pupil to let in more light.įocuses light rays onto the retina. When there is bright light, the iris closes the pupil to let in less light. The colored part of the eye which helps regulate the amount of light entering the eye. The center of the macula which provides the sharp vision. Corrective laser surgery reshapes the cornea, changing the focus. The clear front window of the eye which transmits and focuses (i.e., sharpness or clarity) light into the eye. Structure containing muscle and is located behind the iris, which focuses the lens. Layer containing blood vessels that lines the back of the eye and is located between the retina (the inner light-sensitive layer) and the sclera (the outer white eye wall).
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