See the separate leaflet called Corneal Injury and Foreign Bodies for more details. (Your eye will usually need to be padded shut for this to happen, so that healing is undisturbed.)ĭeeper scratches, such as can be formed by contact lenses which are not well looked-after or cleaned, can leave a permanent scar which can permanently affect vision. The layers of clear cells that form the cornea can spread to fill in a shallow scratch over about 24 hours and they usually heal quickly. Eyes are red and watery, vision is blurry and it may feel as though there is something in your eye. The cornea is very, very sensitive and if it is scraped it hurts. It's not easy for anything to penetrate its globe - but high-speed fragments from drilling or grinding can do so. Penetrating injuries to the eye can affect vision.Active chemicals, such as strong acid, alkali or plaster dust, may damage the surface of the eye and cause scarring.Foreign bodies on the surface of the eye don't normally damage vision but they can do so in certain circumstances: If you get something in your eye then your eye will water, the blinking reflex will be activated and your eye will be very irritable. See the separate leaflets called Eye Problems, Allergic Conjunctivitis and Infective Conjunctivitis for more details. Conjunctivitis does not normally affect your vision, other than to make things slightly blurry due to watering or discharge over the eyes. ConjunctivitisĬonjunctivitis is inflammation or infection of the surface layer of the eye (the conjunctiva). However, if severe they can cause permanent scarring of the clear window (cornea) which sits over the coloured part of the eye (the iris) and the pupil. There are several problems which can affect the surface of the eye which can affect vision, although usually they mainly cause pain and redness. Causes of sudden painful visual impairment Nerve signals pass from the seeing cells in the retina down nerve fibres in the optic nerve to the area of the brain responsible for putting together and interpreting these signals, enabling us to see.įor vision to be clear, the lens of the eye has to be clear (transparent). This is the part of the retina that is the most densely packed with seeing cells (rods and cones). The macula is the part of the retina responsible for our central vision - that is, the things we are looking directly at. It helps to focus the light coming through the eye on to the retina, and in particular the macula. The lens of the eye acts like the lens in a camera. When you look at an object, light from the object passes through the cornea, then the lens, then through the fluid inside the ball (globe) of the eye, until it hits the retina at the back of the eye. Generally speaking, the further towards the back of the eye that problems occur, the more likely they are to have a long-lasting or permanent effect on your eyesight. Problems arising in different parts of the eye can affect vision.
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