AskDefine | Define floater

Dictionary Definition

floater

Noun

1 spots before the eyes caused by opaque cell fragments in the vitreous humor and lens [syn: musca volitans, muscae volitantes, spots]
2 a debt instrument with a variable interest rate tied to some other interest rate (e.g. the rate paid by T-bills)
3 a wanderer who has no established residence or visible means of support [syn: vagrant, drifter, vagabond]
4 an employee who is reassigned from job to job as needed
5 a voter who votes illegally at different polling places in the same election
6 a swimmer who floats in the water
7 an object that floats or is capable of floating
8 an insurance policy covering loss of movable property (e.g. jewelry) regardless of its location [syn: floating policy]

User Contributed Dictionary

English

Pronunciation

Noun

  1. Anything that floats.
  2. An employee of a company who does not have fixed tasks to do but fills in wherever needed, usually when someone else is away.
  3. A threadlike speck in the visual field that seems to move, possibly caused by degeneration of the vitreous humour.
  4. An "extra" male at a dinner party, or a young friend of the hostess, whose assignment is to entertain the female guests.
  5. (insurance) A policy covering property at more than one location or which may be in transit.
  6. (police jargon) A floating corpse picked up from a body of water.
  7. An unaffiliated player.
  8. A maneuver in which a surfer transitions above the unbroken face of the wave onto the lip, or on top of the breaking section of the wave.
  9. A piece of faeces that floats.
    2004: He left a floater in the toilet. — poetry critical workshop http://poetry.tetto.org/read/11410/
  10. A coin which does not spin when thrown in the air.
    1998: In this section "floater" means a spin in which at least 1 of the coins does not turn over in the air at least once. — Queensland government Casino Gaming Amendment Rule (No. 2) 1998 http://www.legislation.qld.gov.au/LEGISLTN/SLS/1998/98SL233.pdf
  11. Someone who attaches themselves to a group of people, much to the dismay of that group, and repeatedly shows up to participate in group activities despite attempts to get rid of, or “flush,” that person.

Derived terms

See also

Extensive Definition

Floaters are deposits of various size, shape, consistency, refractive index, and motility within the eye's vitreous humour, which is normally transparent. They may be of embryonic origin or acquired due to degenerative changes of the vitreous humour or retina. Thus, they generally follow the rapid motions of the eye, while drifting slowly within the fluid. When they are first noticed, the natural reaction is to attempt to look directly at them. However, attempting to shift one's gaze toward them can be difficult since floaters follow the motion of the eye, remaining to the side of the direction of gaze. Floaters are, in fact, visible only because they do not remain perfectly fixed within the eye. Although the blood vessels of the eye also obstruct light, they are invisible under normal circumstances because they are fixed in location relative to the retina, and the brain "tunes out" stabilized images due to neural adaptation. This does not occur with floaters and they remain visible. However, floaters are more than a nuisance and a distraction to those with severe cases, especially if the spots seem to constantly drift through the field of vision. The shapes are shadows projected onto the retina by tiny structures of protein or other cell debris discarded over the years and trapped in the vitreous humour. Floaters can even be seen when the eyes are closed on especially bright days, when sufficient light penetrates the eyelids to cast the shadows. It is not, however, only elderly people who suffer from floaters; they can certainly become a problem to younger people, especially if they are myopic. They are also common after cataract operations or after trauma. In some cases, floaters are congenital.
Floaters are able to catch and refract light in ways that somewhat blur vision temporarily until the floater moves to a different area. Often they trick the sufferer into thinking they see something out of the corner of their eye that really is not there. Most sufferers, with time, learn to ignore their floaters. For people with severe floaters it is nearly impossible to completely ignore the large masses that constantly stay within almost direct view. Some sufferers have noted a decrease in ability to concentrate while reading, watching television, walking outdoors, and driving, especially when tired.: this gel-like substance consists of 99% water and 1% solid elements. The solid portion consists of a network of collagen and hyaluronic acid, with the latter retaining water molecules. Depolymerization of this network makes the hyaluronic acid release its trapped water, thereby liquefying the gel. The collagen breaks down into fibrils, which ultimately are the floaters that plague the patient. Floaters caused in this way tend to be few in number and of a linear form.

Posterior vitreous detachments and retinal detachments

In time, the liquefied vitreous body loses support and its framework contracts. This leads to posterior vitreous detachment, in which the vitreous body is released from the sensory retina. During this detachment, the shrinking vitreous can stimulate the retina mechanically, causing the patient to see random flashes across the visual field, sometimes referred to as "flashers." The ultimate release of the vitreous around the optic nerve head sometimes makes a large floater appear, usually in the shape of a ring ("Weiss ring"). As a complication, part of the retina might be torn off by the departing vitreous body, in a process known as retinal detachment. This will often leak blood into the vitreous, which is seen by the patient as a sudden appearance of numerous small dots, moving across the whole field of vision. Retinal detachment requires immediate medical attention, as it can easily cause blindness. Consequently, both the appearance of flashes and the sudden onset of numerous small floaters should be rapidly investigated by an ophthalmologist.

Regression of the hyaloid artery

The hyaloid artery, an artery running through the vitreous humour during the fetal stage of development, regresses in the third trimester of pregnancy. Its disintegration can sometimes leave cell matter.

Other common causes

Patients with retinal tears may experience floaters if red blood cells are released from leaky blood vessels, and those with a posterior uveitis or vitritis, as in toxoplasmosis, may experience multiple floaters and decreased vision due to the accumulation of white blood cells in the vitreous humour.
Other causes for floaters include cystoid macular edema and asteroid hyalosis. The latter is an anomaly of the vitreous humour, where by calcium clumps attach themselves to the collagen network. The bodies that are formed in this way move slightly with eye movement, but then return to their fixed position.

Treatment

Normally, there is no treatment indicated.
  • Vitrectomy may be successful in treating more severe cases; however, the procedure is typically not warranted in those with lesser symptoms due to the potential for complications as severe as blindness. Floaters may become less annoying as sufferers grow accustomed to them, even to the extent that they may no longer notice them.
  • There is also Sutureless Vitrectomy, as the standard vitrectomy involves cutting through the conjunctiva, or fleshy part of the front of the eye, and making openings in the pars plana area which require stitches at the end of the surgery. In the sutureless technique, small tubes or canulas or trochars are placed through the pars plana area and very tiny instruments are placed through these tubes. Once the surgery is complete, the tubes are removed and no stitches are needed. Only in certain cases can sutureless vitrectomy surgery be performed.
  • Another treatment is laser vitreolysis. In this procedure a powerful laser (usually a Yttrium aluminium garnet laser) is focused onto the floater and in a quick burst vaporizes the structure into a less dense and not as noticeable consistency.

References

See also

floater in German: Mouches Volantes
floater in Spanish: Miodesopsias
floater in Esperanto: Flirtantaj muŝoj
floater in French: Myodésopsie
floater in Italian: Miodesopsie
floater in Dutch: Glasvochttroebeling
floater in Japanese: 飛蚊症
floater in Polish: Męty ciała szklistego
floater in Portuguese: Moscas Volantes
floater in Russian: Деструкция стекловидного тела
floater in Swedish: Mouches volantes
floater in Turkish: Vitre
floater in Chinese: 飛蚊症

Synonyms, Antonyms and Related Words

Ahasuerus, Ancient Mariner, Argonaut, Flying Dutchman, Goliard, Odysseus, Oisin, Ossian, Ulysses, ballot-box stuffer, balloter, bird of passage, bum, derelict, drifter, elector, fraudulent voter, gad, gadabout, go-about, hobo, itinerant, mover, peregrinator, peregrine, peripatetic, proxy, rambler, registered voter, repeater, roamer, rolling stone, rover, runabout, straggler, street arab, stroller, strolling player, tramp, troubadour, vag, vagrant, visitant, voter, wanderer, wandering minstrel, wandering scholar
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