Floater 179636 222552981 2008-06-29T23:26:50Z 74.137.228.83 /* Description */ <!--This article is written in British English with Oxford Spelling. Please keep this in mind when editing this page.--> {{otheruses}} {{Infobox_Disease | Name = Floater | Image = Floaters.png | Caption = Impression of floaters, as seen against a blue sky. | DiseasesDB = 31270 | ICD10 = {{ICD10|H|43|9|h|43}} | ICD9 = {{ICD9|379.24}} | ICDO = | OMIM = | MedlinePlus = 002085 | eMedicineSubj = | eMedicineTopic = | MeshID = | }} '''Floaters''' are deposits of various size, shape, consistency, [[refractive index]], and [[motility]] within the [[eye]]'s [[vitreous humour]], which is normally transparent.<ref name="Cline">Cline D; Hofstetter HW; Griffin JR. ''Dictionary of Visual Science''. 4th ed. Butterworth-Heinemann, Boston 1997. ISBN 0-7506-9895-0</ref><ref name=facts>{{cite web | title = Facts about floaters | publisher = National Eye Institute | date = December 2007 | url = http://www.nei.nih.gov/health/floaters/index.asp | accessdate =February 2008}}</ref> They may be of [[embryo]]nic origin or acquired due to degenerative changes of the vitreous humour or retina.<ref name="Cline"/> The [[visual perception|perception]] of floaters is known as ''myodesopsia'', or less commonly as ''myiodeopsia'', ''myiodesopsia'', or ''myodeopsia''.<ref name="Cline"/> Floaters appear as shadow-like shapes that appear alone or together with several others in one's [[visual field|field of vision]]. They may appear as spots, threads, or fragments of cobwebs, which float slowly before the sufferer's eyes.<ref name=facts/> Since these objects exist within the eye itself, they are not [[optical illusions]] but are [[entoptic phenomenon|entoptic phenomena]]. One specific type of floater is either called ''Muscae volitantes'' (from the Latin, meaning 'flying flies'), or ''mouches volantes'' (from the French), and consist of small spots, these are present in most people's eyes and are attributed to minute remnants of embryonic structures in the vitreous humour.<ref name="Cline"/> ==Description== Floaters are suspended in the vitreous humour, the thick fluid or gel that fills the eye.<ref name=spots>{{cite web | title = Eye floaters and spots; Floaters or spots in the eye | publisher = National Eye Institute | url = http://www.eyecaresource.com/conditions/eye-floaters/ | accessdate = February 2008}}</ref> 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.<ref name=facts/> Floaters are particularly noticeable when looking at a blank surface or an open monochromal space, such as blue sky. Despite the name "floaters", many of these specks have a tendency to sink toward the bottom of the eyeball,{{Fact|date=February 2008}} in whichever way the eyeball is oriented; the supine position (looking up or lying back) tends to concentrate them near the fovea, which is the center of gaze, while the textureless and evenly lit sky forms an ideal background against which to view them.<ref name=spots/> The brightness of the daytime sky also causes the eyes' pupils to contract, reducing the [[aperture]], which makes floaters less blurry and easier to see. Floaters are not uncommon, and do not cause serious problems for most people; they represent one of the most common presentations to hospital eye services. A survey of optometrists in 2002 suggested that an average of 14 patients per month per optometrist presented with symptoms of floaters in the UK alone.<ref>{{Citation |url=http://www.djo.harvard.edu/site.php?url=/physicians/oa/1004 |title= Floaterectomy Versus Conventional Pars Plana Vitrectomy For Vitreous Floaters |publisher=Digital Journal of Ophthalmology |year=2007 |author=Craig Goldsmith |coauthors=Tristan McMullan, Ted Burton |accessdate=2008-04-11}}</ref> 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 [[myopia|myopic]]. They are also common after [[cataract]] operations or after trauma. In some cases, floaters are [[congenital]].<ref name=pre>{{cite web | title = Floaters | publisher =Prevent Blindness America | url = http://www.preventblindness.org/eye_problems/floatersFAQ.html | date= 2005 | accessdate = February 2008}}</ref> 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.<ref name=pre/> ==Causes== There are various causes for the appearance of floaters, of which the most common are described here. Simply stated, any damage to the eye that causes material to enter the vitreous humour can result in floaters. ===Vitreous syneresis=== The most common cause of floaters is shrinkage of the vitreous humour<ref>{{Citation |url=http://www.howtodothings.com/health-and-fitness/a4444-how-to-understand-eye-floaters.html |title=How To Understand Eye Floaters |publisher=howtodothings.com |accessdate=2008-04-11}}</ref>: 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 [[fibril]]s, 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 [[phosphene|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").<ref>{{cite web |url=http://www.agingeye.net/visionbasics/flashesandfloaters.php |title=Flashes & Floaters |accessdate=2008-02-24 |publisher=The Eye Digest }}</ref> 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.<ref name=det>{{cite web | title = Flashes and Floaters (Posterior Vitreous Detachment) | publisher =St. Luke's Cataract & Laser Institute | url =http://www.stlukeseye.com/Conditions/Floaters.asp | accessdate =February 2008}}</ref> ===Regression of the hyaloid artery=== The [[hyaloid artery]], an artery running through the vitreous humour during the [[fetus|fetal]] stage of development, regresses in the third trimester of [[pregnancy]]. Its disintegration can sometimes leave cell matter.<ref>[http://www.healthhaven.com/hyaloid_artery.htm Floaters in fetal development] {{dead link|date=April 2008|url=http://www.healthhaven.com/hyaloid_artery.htm}}</ref> ===Other common causes=== Patients with [[retinal tear]]s may experience floaters if [[red blood cell]]s 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 cell]]s in the vitreous humour.<ref>{{Citation |url=http://www.optometry.co.uk/articles/docs/640c1a5b606a7d89320511ca29ccc288_kabat20010323.pdf |title=A clinician’s guide to flashes and floaters |author=Alan G. Kabat |coauthors=Joseph W. Sowka |publisher=optometry.co.uk |date=[[March 23]], [[2001]] |accessdate=2008-04-10}}</ref> 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.<ref name=det/><ref name=spots/> ===Tear film debris=== Sometimes the appearance of floaters has to be attributed to dark specks in the tear film of the eye. Technically, these are not floaters, but they do look the same from the viewpoint of the patient. People with [[blepharitis]] or a dysfunctional [[meibomian gland]] are especially prone to this cause, but [[allergic conjunctivitis|ocular allergies]] or even the wearing of [[contact lenses]] can cause the problem.{{Fact|date=March 2008}} To differentiate between material in the vitreous humour of the eye and debris in the tear film, one can look at the effect of blinking: debris in the tear film will move quickly with a blink, while floaters are largely unresponsive to it. Tear film debris is diagnosed by eliminating the possibility of true floaters and [[macular degeneration]]. ==Diagnosis== Floaters are often readily observed by a doctor with the use of an [[ophthalmoscope]] or [[slit lamp]]. However, if the floater is a small piece of debris and near the retina they may not be able to observe it even if it appears large to the sufferer. Increasing background illumination or using a pinhole to effectively decrease pupil diameter may allow a person to obtain a better view of his or her own floaters. The head may be tilted in such a way that one of the floaters drifts towards the central axis of the eye. In the sharpened image the fibrous elements are more conspicuous. (If the pinhole is kept moving slowly in small circles, the same technique evokes an interesting [[entoptic phenomenon|entoptic effect]] known as the vascular figure, which is a view of the blood vessels within one's own eye.)<ref name=med>{{cite web | title = Eye floaters and spots | Author =Judith Lee, and Gretchyn Bailey; | Coauthor = Dr. Vance Thompson | publisher = All about vision | url = http://www.allaboutvision.com/conditions/spotsfloats.htm | accessdate = February 2008}}</ref> ==Treatment== Normally, there is no treatment indicated. * [[Vitrectomy]] may be successful in treating more severe cases;<ref>Roth M, Trittibach P, Koerner F, Sarra G. "[Pars plana vitrectomy for idiopathic vitreous floaters.]" ''Klin Monatsbl Augenheilkd.'' 2005 Sep;222(9):728-32. PMID 16175483.</ref><ref name=Vitro>{{cite web | title = Pars plana vitrectomy (PPV) & floater only vitrectomy | url = http://www.eye-floaters.com/treatingfloaters-vitrectomy.php | accessdate = February 2008}}</ref> 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.<ref name=treat>{{cite web | title = Treating eye floaters | url = http://www.eye-floaters.com/treatingfloaters.php |accessdate= February 2008}}</ref> * 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. <ref name=laser>{{cite web | title = Sutureless Vitrectomy | url = http://www.eye-floaters.com/treatingfloaters-suturelessvitrectomy.php | accessdate = February 2008}}</ref> * Another treatment is [[laser]] vitreolysis.<ref name="pmid11913884">{{cite journal |author=Delaney YM, Oyinloye A, Benjamin L |title=Nd:YAG vitreolysis and pars plana vitrectomy: surgical treatment for vitreous floaters |journal=Eye |volume=16 |issue=1 |pages=21–6 |year=2002 |pmid=11913884 |doi=10.1038/sj.eye.6700026}}</ref> 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.<ref name=laser>{{cite web | title = Laser surgery (nd-YAG) | url = http://www.eye-floaters.com/treatingfloaters-lasersurgery.php | accessdate = February 2008}}</ref> ==References== {{reflist|2}} ==See also== {{wikiquote}} *[[Blue field entoptic phenomenon|Blue field entoptic phenomenon, alias Scheerer's phenomenon]] - tiny bright dots moving quickly in the visual field. *[[Phosphene]] *[[Synchysis scintillans]] ==External links== *[http://www.eye-floaters.com/ Eye-Floaters.com - Home of the Eye and Floaters Information Resource] *[http://www.eye-floaters.info/floaters/entoptic_phenomenon-entoptische_erscheinungen.pdf Picture of the entoptic phenomenon: Vitreous Floaters] ([[Portable Document Format|PDF]] file, requires an [[Adobe Acrobat|Acrobat]] Reader or plugin) *[http://www.floatershell.com/floaters-v21.zip Eye floaters - subjective vision simulator] from [http://www.floatershell.com Floatershell.com] *[http://floatertalk.yuku.com Floater Talk - Message board gathering many floater sufferers throughout the world] {{Eye pathology}} {{Visual phenomena}} [[Category:Ophthalmology]] [[Category:Medical signs]] [[Category:Vision]] [[de:Mouches Volantes]] [[es:Miodesopsias]] [[eo:Flirtantaj muŝoj]] [[fr:Myodésopsie]] [[it:Miodesopsie]] [[nl:Glasvochttroebeling]] [[ja:飛蚊症]] [[pl:Męty ciała szklistego]] [[pt:Moscas Volantes]] [[ru:Деструкция стекловидного тела]] [[sv:Mouches volantes]] [[tr:Vitre]] [[zh:飛蚊症]]