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Retinal detachment (also known as amotio retinae) is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized or broad, but without rapid treatment the entire retina may detach, leading to vision loss and blindness. It is almost always classified as a medical emergency. Permanent damage may occur if the detachment is not repaired within 24–72 hours.〔(【引用サイトリンク】title=Retinal Detachment )〕 The retina is a thin layer of light sensitive tissue on the back wall of the eye. The optical system of the eye focuses light on the retina much like light is focused on the film or sensor in a camera. The retina translates that focused image into neural impulses and sends them to the brain via the optic nerve. Occasionally, posterior vitreous detachment, injury or trauma to the eye or head may cause a small tear in the retina. The tear allows vitreous fluid to seep through it under the retina, and peel it away like a bubble in wallpaper. ==Signs and symptoms== A retinal detachment is commonly preceded by a posterior vitreous detachment which gives rise to these symptoms: * flashes of light (photopsia) – very brief in the extreme peripheral (outside of center) part of vision * a sudden dramatic increase in the number of floaters * a ring of floaters or hairs just to the temporal (skull) side of the central vision * a slight feeling of heaviness in the eye Although most posterior vitreous detachments do not progress to retinal detachments, those that do produce the following symptoms: * a dense shadow that starts in the peripheral vision and slowly progresses towards the central vision * the impression that a veil or curtain was drawn over the field of vision * straight lines (scale, edge of the wall, road, etc.) that suddenly appear curved (positive Amsler grid test) * central visual loss In the event of an appearance of sudden flashes of light or floaters, an eye doctor needs to be consulted immediately.〔 A shower of floaters or any loss of vision, too, is a medical emergency. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Retinal detachment」の詳細全文を読む スポンサード リンク
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