Generality
The detachment of the vitreous is a condition in which the vitreous humor - that is the gelatinous substance contained in the vitreous chamber of the eye - tends to detach itself from the retina, to which it adheres, withdrawing towards the center of the eyeball.
Due to the high diffusion that characterizes it (NB: it seems to interest 75% of the population over 65), the detachment of the vitreous is not considered a real morbid condition.
However, in the presence of symptoms attributable to it it is always advisable to contact your doctor, because (although rarely) from a detachment of the vitreous it could achieve a macular hole or a retinal detachment.
There are three characteristic symptoms: vision of "moving bodies" or floaters, photopsy and blurred vision.
Short review of the anatomy of the eye
In the eye (or eyeball ), located in the orbital cavity, three concentric portions can be identified, which, from the outside towards the inside, are:
- The external habit . Area in which cornea and sclera reside, acts as an attack for the so-called extrinsic muscles of the eyeball.
It has a fibrous nature.
- The medium tunic (or uvea ). It is a membrane of connective tissue, rich in blood vessels and pigment.
Interposed between sclera and retina, it deals with providing nourishment to the retina, or rather to the layers of retina with which it comes into contact.
Includes iris, ciliary body and choroid.
- The internal habit . It consists of the retina; the latter is a transparent film, formed by ten layers of nerve cells (or neurons) and with the task of converting light into an electrical signal decipherable by the brain.
The main nerve cells of the retina, which deal with visual function, are the cones and rods. Cones and rods are generally called photoreceptors.
What is vitreous detachment?
The detachment of the vitreous, or posterior detachment of the vitreous, is a condition in which the vitreous humor tends and withdraws from its canonical position, losing the normal and perfect adherence to the retina .
Contained in a space known as the vitreous chamber, the vitreous humor (or vitreous body ) is the gelatinous substance that acts as a support for the crystalline lens, in the front part of the eyeball, and for the retina, in the posterior part of the eye.
Transparent and with a constant volume, the vitreous body consists of 98-99% water and the remaining 1-2% of hyaluronic acid, salts, sugars and collagen- type proteins (vitrosine, opticine, type II collagen, etc.) .
Precisely these collagen-type proteins take care of the adherence between vitreous humor and retina. Thanks to their characteristics, in fact, they are real fibers of conjunction, which keep the two elements "attached".
The vitreous body is devoid of blood vessels and is crossed by the hyaloid canal, which goes from the optic papilla (or the emergence of the optic nerve inside the eyeball) to the hyaloid fossa (ie the posterior part of the crystalline lens).
It is thanks to the aforementioned composition of the vitreous humor that the eyeball maintains its spherical shape.
Causes
The main cause or, if preferred, the most important risk factor for detachment of the vitreous is aging .
In fact, as we age, the vitreous humor tends to lose part of the hyaluronic acid and, after this modification, to become progressively more watery.
Then, as its usual gelatinous consistency disappears, it withdraws from the retina and moves towards the center of the eye. In other words, it loses its strict adherence to the internal habit (which will be remembered as constituted by the retina).
Being a condition strongly linked to advanced age (NB: it generally affects individuals over the age of 65), ophthalmologists do not consider vitreous detachment a morbid condition; rather, they are more inclined to consider it a natural modification to which, sooner or later, many human beings are subjects without other particular reasons.
OTHER RISK FACTORS
In addition to advanced age, other factors such as:
- A strong myopia
- A uveite . For uveitis, it means an inflammatory process against the uvea, or the middle layer interposed between sclera and retina.
- Being subjected to intraocular laser treatment
- A previous intervention of intraocular microsurgery
- A previous ocular trauma
Epidemiology
According to some reliable research, vitreous detachment would affect about 75% of the population over 65; as a demonstration of what has been said, it therefore represents an almost natural consequence of aging.
Other research, then, has shown that it is fairly common even among people aged 40-50.
Symptoms and Complications
Vitreous detachment is a condition more often asymptomatic than symptomatic ; in other words, it generally does not cause any visual disturbance.
In the rare cases in which it is symptomatic, the typical manifestations are:
- Vision characterized by the presence of the so-called "moving bodies" (or floaters) . Some patients describe "moving bodies" as flying flies, others as moving dots and others as spider-like threads.
The size and number of these visual anomalies are extremely variable: there are people who see them as small and others as large; just as there are those who see few and those who see many.
It is not at all uncommon for the same person to claim to see "moving bodies" that, over time, vary in terms of both size and number.
- Vision of flashes, circles and / or sudden light lines. This disorder is called photopsia.
- Blurry vision.
Some individuals with vitreous detachment complain of all three of the above symptoms; others, however, only notice one or two. Therefore, the symptomatology is extremely different from subject to subject.
Important note. Vitreous detachment does not cause any loss of vision and is not painful, so people with the asymptomatic form can completely ignore being affected.
THE DETACHMENT OF THE VITREO RECALLS THE DETACHMENT OF THE RETINA
The characteristic symptoms of vitreous detachment are very reminiscent of the detachment of the retina, a serious morbid condition of the eye that can cause a marked loss of vision or even blindness.
Therefore, in the presence of a vision of "moving bodies", photopsia and / or blurred vision, the experts' advice is to immediately consult a doctor who specializes in eye diseases - or an ophthalmologist - to ascertain the precise cause of the symptoms in progress.
COMPLICATIONS
In a small percentage of cases, detachment of the vitreous may be a cause of injury to retinal damage. In this case, it can determine morbid conditions such as macular hole, retinal rupture and / or retinal detachment .
The macular hole is a condition in which an opening is formed on the macula - the central area of the retina responsible for central vision - which interrupts the normal retinal continuity.
The retinal rupture occurs when a part of the retina is more or less extensively damaged. According to some statistics, 10% of vitreous detachments result in a retinal rupture.
Finally, the retinal detachment occurs when the retina detaches from its supporting tissues, to which, in normal situations, it adheres perfectly.
Rupture and detachment of the retina are two circumstances related to each other, as the former is very often a precursor to the latter. In this regard, statistical studies have shown that about 40% of severe retinal breaks degenerate into a retinal detachment.
Deepening: why can vitreous detachment damage the retina?
As anticipated, vitreous humor and retina are joined together by collagen type proteins.
This union causes the vitro body, when it withdraws towards the center of the eyeball, drags with it what it is tied to, that is the retina.
If it is particularly violent, dragging can cause tears or alterations of the retina or openings at the macula.
TEMPORARY SYMPTOMS OR LASTING TIME?
The symptoms of vitreous detachment almost always have a temporary duration . In fact, they generally last about 6 months, although in some situations they can vanish already after a week or last more than a year.
The more or less extended duration of the symptomatology is not linked to the severity of the detachment . In other words, if the disorders last a year does not mean that the risk of complications is higher; vice versa, if they last a week it does not mean that the detachment of the retina is less likely.
In the next sub-chapter, it will be explained why the symptoms tend to disappear over time.
HOW DO PHOTOPSY AND "MOBILE BODIES" EXPLAIN?
The photopsia occurs when the vitreous body, withdrawing from its natural seat, "pulls" the retina. In fact, every pull on the retinal film generates an electrical signal that the retina itself sends to the brain. Here, this signal is interpreted as a flash, a circle or a line of shining light.
When the vitreous body no longer "tugs" the retina, the photopsia is spontaneously exhausted.
The " moving bodies " appear after the vitreous body has become more watery. In fact, in these conditions, various groups of cells begin to circulate freely within the vitreous chamber, creating a sort of obstacle to the light that enters the eye and is destined for the retina.
When the sunlight hits the cells instead of the retina, shadows form on the retina, which are perceived by our brain as moving points, spider webs or "flying flies".
The "moving bodies" sooner or later disappear for at least two reasons:
- Because the groups of cells vanish (NB: others can form and the problem can recur in these situations).
- Because the brain "gets used" and ignores its presence. This could take up to several months.
IS DETACHMENT OF VITREO IS MONO OR BILATERAL?
The vitreous detachment can be either unilateral - that is to say on one eye only - or bilateral, or on both eyes.
Generally, when it is due to aging, it is a bilateral condition, which affects the eyeballs at different times.
Diagnosis
Ophthalmologists establish the diagnosis of vitreous detachment by careful examination of the ocular fundus .
This evaluation is based on the use of a particular instrument - the so-called slit lamp - that allows the vision of the internal structures of the eyeball, from the vitreous humor to the retina.
To obtain the greatest number of indications, eye drops are usually used which dilate the pupil. This preparation works within 30 minutes and ends its effects after 6 hours. During this time, it is strongly advised against driving a vehicle, for the safety of the patient and other road users.
From the instrumental point of view, the slit lamp - in front of which the individual under examination must ask - is a sort of microscope that emanates a powerful but completely harmless light beam for the health of the eye.
The examination of the ocular fund allows doctors to also identify possible pathologies of the retina, such as the macular hole or retinal detachment.
Treatment
Currently, there is no specific treatment for vitreous detachment .
Moreover, numerous experimental tests have revealed that, as regards the symptomatological aspect, the exercises for the eyes, some particular diets (once considered effective) and the daily intake of certain vitamins are completely useless.
Therefore, in most cases, the only solution is to wait for the spontaneous disappearance of the symptoms, the latter event which - as we have seen - generally takes place within 6 months.
LASER AND VITRECTOMY
In the past, ophthalmologists have discussed the effectiveness of laser treatment and vitrectomy for persistent myopia.
After several experimental tests and the analysis of numerous clinical cases, they observed that:
- Laser therapy is only effective in one third of cases of vitreous detachment and the risk of complications is greater than the benefits associated with treatment.
- Vitrectomy has an unbalanced benefit / risk ratio to the latter, so it is not worth implementing it.
What is vitrectomy?
Vitrectomy is the surgical procedure of total or partial removal of the vitreous body, carried out in order to cure a pathology of the retina and / or macula, a vitreous hemorrhage, an ocular trauma, etc.
It requires local or general anesthesia and can involve various complications, including: cataract, retinal detachment, infection or increased eye pressure.
To know in detail what the whole vitrectomy procedure involves, it is advisable to consult the article on this page.
TREATMENTS IN CASE OF COMPLICATIONS
If the detachment of the vitreous leads to the onset of a macular hole or a lesion of the retina (whether it is a break or a retinal detachment), it is necessary to intervene as soon as possible.
In fact, failure to treat these conditions can lead to severe vision loss and, in some cases, even blindness.
- In the case of a macular hole, there are two treatments: vitrectomy, which is indicated for all cases of macular hole, and the injection of ocriplasmin, which is suitable only for some particular cases of macular hole.
- In the presence of retinal breaks, the most widely practiced treatment is laser surgery.
- For retinal detachment, the treatment method adopted depends on the severity of the situation.
In case of minor detachments, laser surgery, cryopexy and pneumoretinopexy may be sufficient; in cases of severe detachment, instead, it is necessary to resort to the application of a so-called scleral buckle or vitrectomy.
ACTIVITIES? IN FREE TIME
Most patients with a vitreous detachment can continue to perform, in their free time, the same activities (work, sports, etc.) that they practiced before sight problems.
In fact, the numerous scientific studies conducted in this regard have not reported any particular contraindication in performing a certain job or a certain sport.
Prognosis
Unless it leads to injuries to the retina and / or macula, the detachment of the vitreous is a condition with a non-negative prognosis.
