Vitreous

The eye is filled, for 4/5 of its volume, of a viscous liquid, transparent, avascolare, similar to the clear egg, (made for 99% of water and the remaining 1% fibers of collagen and hyaluronic acid), said precisely vitreous. Perfectly transparent and adherent to theretina(by a membrane, thisinternal limiting) and tocrystalline, fills every space in the vitreous cavity. There are many functions of the vitreous ranging from metabolic function and nourishment by filtering and selecting the molecules that pass through it, preventing cell transmigration inside being inelastic and impermeable, function diopter, as it is perfectly transparent, to the filling station and of absorption of external microtrauma bulbar, that respond to inflammation because it has degenerative and proliferative capacity. Also, considering the rapid eye movements and violent tractions exerted on the bulb by the eye muscles and then the tangential tractions internal demand placed on them particularly sensitive structures such as the retina and the lens, the vitreous performs a particular function of protection of these tissues. In the young has 3 areas of particular adherence to the retina, all’hour lockout the most peripheral and front of this, an annular area around large 4 mm thisthe vitreous base which is the most tenacious is present a residual adhesion for life, at the level ofoptic disc the head of the optic nerve to the posterior pole of the eye and along the arterial and venous vessels main. With the passing of years, the loss of consistency of hyaluronic acid is responsible for the"Fluidization" the posterior portion of the vitreous (process that increases with age, above the 80 years more than half of the gel is liquefied) and the formation of gaps in vitreous liquefied. The collagen fibers (that constitute '"scaffolding" of vitro), aggregate into larger filaments ("Vitreous syneresis"(already present in the 5% of the subjects from 21 to 40 age). These fibrillar aggregates, more or less dense, float in fluidized areas with characteristic post-movement, being perceived by the patient as floaters, strands of spider web, etc. said by ophthalmologists "floaters or floaters". The further liquefaction of the vitreous and the coalescence of the gaps vitreous leads to the collapse of the vitreous that led "posterior vitreous detachment phenomenon that often seriously alarmed the patient consisting of the loss of adhesion of the vitreous to the optic disc and retinal vessels. I “floaters or miodesospsie are due to condensation of the vitreous collagen (much more rarely blood clots after an organized vitreous hemorrhage, trauma, flocs or post-inflammatory), by collagen fibers and hyaluronic acid. The ability of the latter to bind water molecules is the basis of maintaining the structure of the vitreous gel. The retinal cells are unable to feel pain, temperature and pressure to which is realized when the posterior detachment of the vitreous is not felt no pain or tension of the eye, but only the perception of many mobile bodies sometimes associated with bright flashes. Floaters floating in the liquefied vitreous, move according to the movements of the eye, but have post-movement, that is, when the eye stops, continue their course of inertia. They are therefore perceivednot as fixed spots, but as shells which follow the wave motion above the sand. Although annoying, it is still benign manifestations that in most cases, especially the smaller ones resolve themselves in a few months and do not have a direct influence on the state of ocular. Only a small percentage of cases are larger and tend to persist for years, bringing a considerable inconvenience in daily life. However, about 15% of patients with symptomatic severe separation of the vitreous (associated with lightning, numerous bodies furnitures or blurred vision) features of peripheral retinal breaks and if it is associated vitreous hemorrhage risk of having retinal tears rising to 70%. So the perception of a miodesospsia, small or large, requires careful monitoring of the fundus by an ophthalmologist to be repeated about 4-6 weeks later in the case of incomplete vitreous detachment or peripheral lesions of the retina at risk.