Vitreous detachment is a pathological condition in which the interaction between the vitreous body and the retina is disrupted. It occurs as a result of degenerative changes in the vitreous body, in the presence of high-grade myopia, inflammatory processes or after an eye injury. A complete or partial detachment is isolated. Clinically manifested by the occurrence of photopsias, flashes, lightning when moving the eyeballs. Ophthalmometry, visometry, tonometry, biomicroscopy, ultrasound of the eye, FRA measurement are used for diagnostics. Treatment is only surgical, it consists in vitrectomy or enzyme vitreolysis.
General information
Vitreous detachment is a disease of the vitreous body in which, as a result of degenerative changes, there is a progressive weakening of basal vitreoretinal adhesion. The vitreous body is located in close proximity to the retina of the eye, which determines the importance and relevance of this pathology. With vitreous detachment, depending on the strength of vitreomacular traction, damage to the macular region may occur, which is a formidable complication, accompanied by loss of vision, decreased ability to work and disability. Pathology occurs at the age of over 50 years, is more often diagnosed in women than in men. There is no relationship with race or country of residence.
Etiology
The etiological factors of the development of vitreous detachment in ophthalmology include old age and the presence of high–grade myopia – degenerative changes in the structures of the eye begin to occur after 50 years, vitreoretinal adhesion and the amount of collagen in the vitreous body significantly decrease. Frequent inflammatory diseases of the retina and vascular membranes of the eye are also considered as a predisposing factor. With these pathologies, the pH changes to the acidic side, disturbances occur in the cellular structures of the vitreous body, the level of adhesion between the inner boundary membrane and the posterior hyaloid membrane decreases.
The probability of vitreous detachment increases with some common diseases, including diabetes mellitus, Marfan syndrome, thyroid pathology. As a result of hormonal disorders associated with these diseases, the synthesis of hyaluronic acid and glycosaminoglycans is disrupted in the body, as a result, the structure of the vitreous body changes, detachment occurs. In addition, penetrating wounds and surgical treatment of the eyeball are among the circumstances that increase the risk of vitreous detachment.
Pathogenesis
The main reason for the development of vitreous detachment is a violation of the interaction of the posterior hyaloid membrane (PHM) of the vitreous body and the inner boundary membrane (IBM) of the retina. The hyaloid membrane of the vitreous body consists of collagen fibers, hyalocytes, a special protein fibronectin and laminin (they are the basis of the intercellular matrix). It forms the outer layer of the vitreous body, which adheres to the retina of the eye. The inner membrane of the retina contains collagen fibers, hyaluronic acid, and the plasma membrane of the Muller cells of the retina. The thickness of the boundary membrane of the retina varies. The smallest thickness and stronger connection with the vitreous body are noted around the vessels of the retina, the optic nerve disc and the macular region. The rest of the length reveals a thickening of the membrane and a less strong connection.
Depending on the penetration of vitreal fibrils into the retinal layers, on the one hand, the presence of fibronectin and laminin, on the other hand, determines the strength of contact between the vitreous body and the retina of the eye. With age (more often after 50 years), the border membrane of the retina thickens, which reduces the ability of Muller cells to produce intercellular substance and maintain its normal level. This leads to a weakening of the vitreoretinal connection with the subsequent detachment of the boundary membrane from the hyaloid, as a result, vitreous detachment develops.
Classification
Depending on the nature of the detachment, a complete and partial separation of the vitreous body is distinguished. With complete detachment, the vitreous body is detached from the OND with the formation of a peripapillary space. This type of detachment is more common at a young age, when the vitreous gel has a more decorated structure, and the separated glial membrane is transparent. In addition, this type of detachment occurs when the vitreous body is separated from the OND as a result of the penetration of inflammatory exudate from the chorioretinal focus (possibly with posterior uveitis) or the presence of hemorrhage between the vitreous body and the retina of the eye.
Partial detachment of the vitreous body can develop as a result of inflammatory diseases of the retina of the eye (choroiditis, retinitis), retinal hemorrhages, thrombosis or penetrating wounds of the eye. Separation occurs from the base of the vitreous body, behind the lens, or from the exit point of the OND (while maintaining contact throughout the rest). Pathological detachment of the vitreous body is determined in cases of contact of the vitreous body with the retina only on the periphery of the fundus. The causes may be complications after surgical removal of the lens, inflammatory diseases of the retina (chorioretinitis) or penetrating eye injuries.
Symptoms and diagnosis
Clinical manifestations depend on the type of vitreous detachment. With complete detachment, the patient submits complaints to the ophthalmologist about photopsias, flashes, lightning when moving the eyeballs. Various floating inclusions may appear in the field of view, from “flies” to large geometric shapes. With partial detachment, there may be no complaints, sometimes the pathology of the vitreous becomes an accidental find. The lesion is bilateral, visual acuity does not decrease. Complications include the development of regmatogenic retinal detachment or macular foramen, which occur as a result of pathological traction of the vitreous body to the macula area. In patients with diabetic retinopathy, complete detachment of the retina of the eye is possible.
For diagnosis, standard examination methods are used: visual acuity determination, ophthalmometry, refractometry, tonometry, ophthalmoscopy, biomicroscopy. Of the additional methods, the determination of the anteroposterior axis of the eye is used (the risk of vitreous detachment increases with a FRA of more than 24 mm). Ultrasound of the eyeball is used (allows to visualize structural changes in the vitreous body, to detect the presence of traction or detachment in the retina) and optical computed tomography (makes it possible to study in detail the condition of the retina, measure the thickness of PHM and IBM).
Treatment and prevention
Treatment is only surgical, carried out in the presence of complications. Without clinical manifestations and complaints of the patient, vitreous detachment does not require special measures. The development of complications, such as retinal detachment, is an indication for surgical intervention. Various variants of vitrectomy with the removal of the posterior hyaloid membrane are used. In addition, enzyme vitreolysis can be used – the introduction of a special medicinal substance into the vitreous body to change the chemical and physical properties of its molecules and weaken vitreoretinal adhesion. The prognosis is favorable only with timely treatment.
Preventive measures are aimed at reducing the risk of complications. Adequate treatment of concomitant diseases, such as diabetes mellitus or thyroid pathology, is necessary. Diet, abstinence from alcohol and smoking have a positive effect on the prognosis of this pathology. The list of preventive measures also includes a rational work and rest regime for the eyes, compliance with safety regulations to prevent injuries to the visual organ. If symptoms of vitreous detachment appear, it is necessary to contact an ophthalmologist as soon as possible for a detailed examination.
