The vitreous body is a transparent structure that fills much of the posterior segment of the eye. It is a gelatinous structure that participates in maintaining the shape of the eye as well as mechanically supporting the retina. It is anchored to the inner walls of the eye including the retina.
The vitreous consists mainly of water (99 percent), but it also contains hyaluronic acid and the proteins that make up its scaffolding: collagen.
It is located behind the lens and precedes the retina; light must pass through the entire vitreous body to reach the retina.
Consequently, in order for light not to encounter obstacles, the vitreous body should always be perfectly transparent.
Myodesopias, better known as flying flies, are opacities of the vitreous, the result of degenerative phenomena that affect the hyaluronic acid and mainly the collagen contained in the vitreous. Thus, mobile bodies are no longer transparent but visible vitreal proteins floating in the vitreous in front of the retina.
They are to be considered visual disorders characterized by the sensation of the presence of corpuscles within the visual field, as if structures of various shapes, often irregularly shaped, were present between the eye and the object being looked at. They do not appear stationary but seem to somehow float in the air hence the name also mobile vitreous bodies.
Moving bodies are perceived much more clearly when looking at light or very bright surfaces such as the white walls of a room or looking at a panorama on a clear day. Conversely, in dimly lit environments it can vary and make moving bodies less visible.
The summer period is a critical time as outdoor living and the increased amount of daylight hours can give the feeling of apparent deterioration as they make moving bodies more noticeable. It should also not be forgotten that the vitreous is composed of 99% water so that in summer increased sweating leads to dehydration sometimes even accentuated, which also affects the vitreous by accentuating the perception of mobile bodies.
Changes in the vitreous body can also be very early, in many cases being evident as early as 20 years of age. With age, which is the main cause of myodesias, the phenomenon progresses. Risk factors for early vitreous degeneration include myopia, especially if it is medium to severe.
The degenerative phenomenon, therefore, progresses over time and the vitreous undergoes true liquefaction, also leading to a loss of the mechanical support function of the vitreous particularly toward the retina, which is subjected to mechanical stresses particularly so-called vitreal tractions. Vitreous liquefaction and structural changes can result in vitreous detachment, which occurs asymptomatically in most cases.
It has been mentioned, however, that the vitreous is anchored to the inner walls of the eye and therefore also to the retina, in some rare cases, therefore, vitreous detachment can also result in retinal detachment, which is the greatest risk when we start of vitreous degeneration. Myodesopias, therefore, are a symptom that should not be overlooked and should be followed up over time with regular eye examinations.