Epiretinal membrane is a slowly progressive disease that develops as a result of the formation of a thin film in the vitreous cavity. Clinical symptoms are represented by a decrease in visual acuity, the appearance of “fog” and distortion of the image in front of the eyes, diplopia. Diagnostics includes ophthalmoscopy, Doppler ultrasound in In-mode, visometry, tonometry, OCT, fluorescent angiography. The tactics of surgical intervention of the epiretinal membrane is reduced to performing vitrectomy. Conservative treatment due to the high risk of complications is not used.
H43.3 Other opacities of the vitreous body
The epiretinal membrane is a thin fibrocellular structure devoid of its own blood supply, which is located in the thickness of the vitreous body near the macula. The disease was first described in 1955 by scientist H. Kleinert. Epiretinal membrane is almost twice as often diagnosed in patients after 60 years. In patients under 60 years of age, pathology is detected in 3.7% of cases. In the group from 61 to 70 years of age, this indicator is at the level of 6.6%. In 7% of the population, diagnosis occurs at the initial examination by an ophthalmologist. The disease is more common among women. According to statistics, in 28.6% of cases the disease progresses, in 25.7% its reverse development is observed and in 38.8% the pathological process remains stable.
In most cases, the etiology of the epiretinal membrane is associated with involutional changes in the fundus. Specialists in the field of ophthalmology have described cases of the disease against the background of diabetic retinopathy, traumatic injuries, myopia, vitreous detachment or retinal detachment. If the cause of its formation cannot be established, we are talking about the idiopathic development of pathology.
The trigger of the secondary form may be thrombosis of the central retinal vein. Also, the occurrence of thrombosis is often caused by intravitreal hemorrhage. Stimulates the formation of the epiretinal membrane cryopexy, which is used in the treatment of rupture or detachment of the inner shell of the eyeball. At the same time, pigmentocytes predominate in the composition of the membrane.
The secondary form of the disease is more often detected in patients with a history of inflammatory diseases of the visual organ. The epiretinal membrane may develop in the postoperative period after surgical intervention in connection with cataracts, laser coagulation of the retina in proliferative diabetic retinopathy or proliferative vitreoretinopathy.
Synthesis of this structure occurs due to glial cells, the leading role among which is assigned to fibrous astrocytes. These cells appear in the vitreous body due to damage to the retina or the posterior parts of the gelatinous substance. The role of retinal pigmentocytes, monocytes and macrophages in the formation of the epiretinal membrane has been proved. Pronounced proliferative processes lead to the formation of folds on the inner shell of the eye and the development of tangential traction.
The epiretinal membrane does not have its own vessels, it is located in the posterior pole of the eye. Localized in the thickness of the vitreous body, it is located near the macula. The long course of the disease leads to the fact that the structure of the membrane changes, the thin film is replaced by scar tissue. Further, the pathological formation gradually tightens the retina, thereby provoking the outflow of surrounding structures in the macular zone. The final stage in the pathogenesis of the epiretinal membrane is the rupture and detachment of the retina.
Symptoms of epiretinal membrane
The disease is characterized by a slowly progressive course. One eye is more often affected. In the case of binocular development, the morphological picture is asymmetric. From a clinical point of view, there are primary and secondary forms. Often, the disease has a latent course for a long time. The first symptoms of pathology are a decrease in central vision, the appearance of “fog” in front of the eyes. Image distortion soon develops, which is associated with the formation of folds on the inner shell of the eyeball, ectopia of the central fossa, as well as an increase in the density of the epiretinal membrane.
When the pathological process spreads to the macula, edema occurs, which is subsequently replaced by the formation of defects and detachment. At the same time, patients complain about the appearance of photopsias and metamorphopsias. In the case of concomitant rupture of retinal vessels, “flies” or black dots in front of the eyes are observed. After complete detachment, patients note the appearance of a dark shadow or “veil”, rapid deterioration of visual functions. The progression of pathology leads to a decrease in visual acuity. A specific symptom of the disease is diplopia, which persists even when the eyelids of one eye are closed.
A complication of the epiretinal membrane is traction swelling of the macula, which occurs when the pathological formation or vitreomacular traction is reduced. It is possible to eliminate the manifestations of complications only surgically.
Diagnosis of the disease is based on the results of ophthalmoscopy, ultrasound (Doppler ultrasound), visometry, tonometry, optical coherence tomography (OCT), fluorescent angiography.
- During ophthalmoscopy, the epiretinal membrane has a brilliant shade, which is why many authors describe it as “cellophane retinopathy”. At stage Ia, a small yellowish formation appears in the central fossa of the inner shell of the eye. In Ib, a flat contour of the central fossa resembling a yellowish circle is observed, in II – a violation of the structure of the retina up to 400 microns in diameter, in III – a retinal defect of more than 400 microns, in IV – a complete defect with the formation of Weiss rings.
- Ultrasound is used in the process of diagnosing the epiretinal membrane with uninformative ophthalmoscopy (cataract, opacity of the cornea or vitreous). In the B-mode, hyperechoic formation is detected in the vitreous body area. Depending on the intensity of the echo signal, its density can be judged.
- OCT allows you to visualize a thin membrane in front of the central fossa, detect defects in the retina, the presence of exudate and macular edema.
- Fluorescence angiography is performed to assess the severity of edema and abnormalities of the vascular membrane of the eyeball. When filling the vessel with a fluorescent substance, filling defects, changes in wall thickness, areas of thrombosis, embolism or rupture are noted. Also, against the background of intensely colored vessels of the inner shell of the eye, an epiretinal membrane deprived of its own blood supply is found.
- Visometry is performed to determine the degree of visual acuity reduction. An increase in the size of the membrane leads to an increase in intraocular pressure. In order to measure it, non-contact tonometry is shown.
Treatment of epiretinal membrane
Due to the pronounced toxic effect on the organ of vision of medications that were previously used for treatment, preference is now given to surgical tactics. Indications for surgical intervention are a strong decrease in visual acuity, a high risk of macular damage. At the first stage of the operation, a vitrectomy is performed. In this case, the posterior and central parts of the vitreous body are removed, provided that the patient has his own lens. In the event that the lens is missing or there is an artificial implant, resection of the anterior part of the vitreous body together with the lens is additionally performed. Also, pronounced adhesive processes become an indication for joint removal.
The next stage of surgery is the removal of the epiretinal membrane. In this case, the pathological formation for its outer edge is slightly raised above the inner shell of the eyeball. A thin tweezer is used for removal. The inner boundary membrane is excised after the previous staining with special dyes. After that, at the final stage of the operation, a thorough revision is carried out in order to identify damage to the retina in the posterior pole area or in the peripheral parts. If ruptures are detected that are not burdened by the accumulation of exudate or transudate in the subretinal space, laser retinopexy or cryoretinopexy is performed.
Surgical intervention is performed as planned, but in the case of severe macular edema, urgent hospitalization with urgent resection of the epiretinal membrane is indicated. Surgical treatment does not affect the etiology of the disease, therefore, as a result of cell proliferation, a relapse of the disease is possible.
Prognosis and prevention
No specific prevention measures have been developed. Non-specific preventive measures are aimed at pathogenetic mechanisms of development and are reduced to the control of hormonal status, prevention of thrombosis and embolism, compliance with safety rules at work. Patients with an established diagnosis of “epiretinal membrane”, as well as after surgery, should be examined by an ophthalmologist 2 times a year, since 10% of patients have relapses. Timely diagnosis and surgical treatment provide a favorable prognosis. With a marked decrease in visual functions, the therapy only partially restores visual acuity.