- detached retina
Separation of most layers of the retina of the eye from the choroid, the pigmented middle layer of the eyeball.With age, small tears can develop in the retina, and the vitreous humour inside the eyeball leaks through, separating the retina from the choroid. The disease retrolental fibroplasia or accidents can also cause retinal detachment. It usually develops slowly, without pain. Floating black spots and flashes of light appear in the affected eye, and vision becomes increasingly blurred. Without prompt treatment, it causes permanent blindness. Draining the fluid behind the retina and applying heat, a laser beam, or extreme cold causes scarring that seals the tears and prevents the retina from detaching again.
* * *▪ medicineeye (eye, human) disorder involving separation of the transparent light-sensing portion of the retina from the underlying layer of supporting cells known as the retinal pigment epithelium. Most commonly, retinal detachments are caused by the passage of fluid through a break, or tear, in the retina, a situation called rhegmatogenous retinal detachment. The fluid is derived from the aging vitreous gel that fills the central eyeball space. The retinal break can result from a number of different mechanisms, including trauma or degenerative changes in the peripheral retina.Most retinal breaks or tears, however, are the result of the natural changes of the vitreous gel that are often experienced with aging. The vitreous gel is physically attached to the retina, but, if the gel pulls away, the gel's surface usually releases its hold, creating a benign posterior vitreal detachment without a retinal tear. If, however, a portion of the retina is torn during this process, the likelihood that a retinal detachment will soon follow is high. Unfortunately, the symptoms of a benign posterior vitreous detachment and a serious retinal tear are similar. These symptoms include the onset of many “floaters” (deposits in the eye that cause visual spots or shadows), as well as brief, flashing lights in the affected eye. The presence of bleeding within the eye under these circumstances greatly increases the chances that there is a retinal tear. Concern for subsequent retinal detachment is heightened if there is a perception of a gray or black curtain, or veil, being drawn across the eye's visual field.Not all retinal breaks need treatment, but those that do (especially those associated with a retinal detachment) are often treated with laser, freezing, or a variety of surgical interventions. Failure to reattach the retina in a timely manner can lead to permanent vision loss. Retinal detachment repair is considered more urgent if the centre of the retina (the macula) is still attached, since progression of the detachment to include the macula significantly decreases the prognosis for good postoperative vision. Other types of retinal detachments include tractional detachments, which are caused by abnormal membranes that contract on the surface of the retina (as can occur with advanced diabetic eye disease), and exudative detachments, in which the fluid that leaks under the retina comes from within or beneath the retina.
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См. также в других словарях:
detached retina — de·tached retina di tacht n RETINAL DETACHMENT * * * see retinal detachment * * * a retina whose inner layers are separated from the pigment epithelial layer; see retinal detachment, under detachment … Medical dictionary
detached retina — noun visual impairment resulting from the retina becoming separated from the choroid in the back of the eye; treated by photocoagulation • Syn: ↑retinal detachment, ↑detachment of the retina • Hypernyms: ↑visual impairment, ↑visual defect,… … Useful english dictionary
detached retina — /dətætʃt ˈrɛtənə/ (say duhtacht retuhnuh) noun a condition in which the retina comes away from the back of the eye, potentially resulting in blindness. Also, retinal detachment … Australian English dictionary
detached retina — Synonyms and related words: amaurosis, blepharitis, cataract, choroiditis, conjunctivitis, cross eye, defective vision, esotropia, eye defect, glaucoma, gutta serena, iritis, keratitis, optic neuritis, pink eye, retinoblastoma, sty, trachoma,… … Moby Thesaurus
detached retina — see retinal detachment … The new mediacal dictionary
retina — /ret n euh, ret neuh/, n., pl. retinas, retinae /ret n ee /. Anat. the innermost coat of the posterior part of the eyeball that receives the image produced by the lens, is continuous with the optic nerve, and consists of several layers, one of… … Universalium
retina — n. a detached retina * * * [ retɪnə] a detached retina … Combinatory dictionary
Retina — The retina is the nerve layer that lines the back of the eye, senses light, and creates impulses that travel through the optic nerve to the brain. There is a small area, called the macula, in the retina that contains special light sensitive cells … Medical dictionary
Retina, detached — A retina that separates from its connection at the back of the eye. The process of retinal detachment is usually due to a tear (a rip) in the retina, often when the vitreous gel pulls loose or separates from its attachment to the retina, most… … Medical dictionary
detached — adjective 1》 separate or disconnected. ↘(of a house) not joined to another on either side. 2》 aloof and objective. 3》 denoting a retina that has become separated from the underlying choroid tissue at the back of the eye, causing loss of… … English new terms dictionary