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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're 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 don't remain perfectly fixed within the eye. Although the blood vessels of the eye also obstruct light, they're invisible under normal circumstances because they're fixed in location relative to the retina, and the brain "tunes out" stabilized images due to neural adaptation. This doesn't 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're 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 isn't there. Most sufferers, with time, learn to ignore their floaters. For people with severe floaters it's 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's 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.Further Information

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