Together with the lens, the cornea bends (refracts) light to focus it onto the back of the eye.Ĭrystalline lens - A transparent adjustable lens that sits behind the iris. Iris - The coloured part of the eye that controls the amount of light passing through the pupil.Ĭornea - A transparent dome that protects the iris and pupil. Pupil - The black hole at the centre of the coloured iris, it allows light through. Sclera - The ‘white’ of the eye that protects the eyeball and gives it it's firm, regular shape. Eyebrows are arched in shape to divert sweat away from your eyes.īelow are the component parts of the eye and a brief explanation of their role in allowing you to see the world around you. Eyelashes and eyelids keep out dust and dirt. Protecting - The eyes are recessed into sockets in the skull to protect them from injury. Emotional tears are a response to sadness or joy. Reflex tears protect the eye from irritants like smoke, dust and wind. Tears are also bactericidal so they help prevent infections.Ĭrying - Tears are salty fluid containing protein, water, mucus and oil – are released from the lacrimal gland in the upper, outer region of the eye. We really appreciate this in dusty / windy conditions. ![]() If your eyes don't move together you will see double.īlinking - Every time you blink, a salty secretion (basal tears) from your tear gland is swept over the surface of the eye, keeping your eyeballs moist and clean. Four move the eyeball up, down, left and right two adjust the eyes to counterbalance head movement. Moving - The six ‘extraocular’ muscles control the movement of the eye. Seeing - Eyes take in light and convert it into electrical impulses that are sent to the brain, which processes these signals to form the images we see. ![]() Here are some of the main functions that help the eye make clear, single images. Your eyes play a crucial role in almost everything you do. ![]() The brain processes the signals to create an image.The electrical impulses are sent along the optic nerve to the brain.Photoreceptors on the retina convert the light into electrical impulses.The cornea and lens bend (refract) the light to focus onto the retina.Light passes through the cornea, the pupil and the lens.Light reflects off objects and travels in a straight line to your eye.Learn more about how light passes through the eye to the retina and sends signals through the optical nerve, to your brain. 28, 2020.Your eyes take in vast amounts of information about what’s around them, sending signals to the brain so you can see shapes, colours, texture and movement. Age-related macular degeneration preferred practice pattern - 2019. Have AMD? Save your sight with an Amsler grid.Evaluation of the ophthalmologic patient.Complex retinal detachment: Proliferative vitreoretinopathy and giant retinal tears.It slowly affects the retina and causes loss of night and side vision. Retinitis pigmentosa is an inherited degenerative disease. Many people will first have the dry form, which can progress to the wet form in one or both eyes. There are two types - wet macular degeneration and dry macular degeneration. This causes symptoms such as blurred central vision or a blind spot in the center of the visual field. In macular degeneration, the center of your retina begins to deteriorate. The hole may develop from abnormal traction between the retina and the vitreous, or it may follow an injury to the eye. A macular hole is a small defect in the center of the retina at the back of your eye (macula). This membrane pulls up on the retina, which distorts your vision. Epiretinal membrane is a delicate tissue-like scar or membrane that looks like crinkled cellophane lying on top of the retina. Or you may develop new, abnormal capillaries that break and bleed. This causes the retina to swell, which may blur or distort your vision. If you have diabetes, the tiny blood vessels (capillaries) in the back of your eye can deteriorate and leak fluid into and under the retina. This usually occurs when fluid passes through a retinal tear, causing the retina to lift away from the underlying tissue layers. A retinal detachment is defined by the presence of fluid under the retina. It's often accompanied by the sudden onset of symptoms such as floaters and flashing lights. A retinal tear occurs when the clear, gel-like substance in the center of your eye (vitreous) shrinks and tugs on the thin layer of tissue lining the back of your eye (retina) with enough traction to cause a break in the tissue. TypesĬommon retinal diseases and conditions include: ![]() Untreated, some retinal diseases can cause severe vision loss or blindness. Depending on your condition, treatment goals may be to stop or slow the disease and preserve, improve or restore your vision. Treatment is available for some retinal diseases.
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