Age-related macular degeneration is an involutional dystrophic changes affecting mainly the choriocapillary layer of the vascular membrane of the eye, the retinal pigment layer and the vitreous plate located between them (Bruch’s membrane). The symptoms include distortion of straight lines, the appearance of blind spots in the field of vision, flashes of light, loss of clarity of vision, ability to write and read. The diagnosis is confirmed by ophthalmoscopy, visual acuity testing, Amsler test, campimetry, laser scanning tomography, perimetry, electroretinography, fluorescent angiography of retinal vessels. In age-related macular degeneration, medication, laser, photodynamic therapy, electro- and magnetostimulation, as well as vitrectomy, revascularization and vasoreconstruction of the retina are performed.
H31.1 Degeneration of the vascular membrane of the eye
In clinical ophthalmology, age-related macular degeneration (age-related macular degeneration) refers to vascular pathology of the eye and is characterized by gradual irreversible changes in the macular region of the retina with significant loss of central vision of both eyes in patients older than 50 years. Even in severe cases, this disease does not cause complete blindness, since peripheral vision remains within normal limits, but the ability to perform clear visual work (reading, writing, transport management) is completely lost.
Age-related macular degeneration is a multifactorial pathology, the mechanisms of occurrence and development of which are not fully clear. This disease can develop as a congenital disease with an autosomal dominant type of inheritance or be a consequence of infectious-inflammatory, toxic and traumatic lesions of the eye.
The development of age-related macular degeneration may be based on primary involutional changes in the macular region of the retina and Bruch’s membrane, atherosclerosis and microcirculation disorders in the choriocapillary layer of the vascular membrane, the damaging effect of ultraviolet radiation and free radicals on the pigment epithelium, metabolic disorders.
The risk zone for age related macular degeneration includes persons
- over 50 years of age, predominantly female, with light pigmentation of the iris;
- with immune and endocrine pathology, arterial hypertension;
- abusers of smoking;
- who have undergone cataract surgery.
According to the pathogenesis, the following forms of age-related age-related macular degeneration are distinguished: dry atrophic (non-exudative) and wet (exudative).
- Dry age-related macular degeneration. The early form of the disease, which occurs in 85-90% of cases, is accompanied by atrophy of the pigment epithelium and a gradual decrease in vision, and the lesion of the second eye develops no later than 5 years after the disease of the first.
- Wet age-related macular degeneration. In 10% of cases, dry age-related macular degeneration turns into a more severe and fast-flowing exudative form, complicated by detachment of the retinal pigment and neuroepithelium, hemorrhages and scar deformation.
The clinical course of age-related macular degeneration is chronic, slowly progressing. In the initial period of the non-exudative form of age-related macular degeneration, there are no complaints, visual acuity remains within the normal range for a long time. In some cases, distortion of straight lines, shape and size of objects (metamorphopsy) may occur.
Dry age-related macular degeneration is characterized by accumulations of colloidal matter (retinal druses) between the Bucha membrane and the retinal pigment epithelium, pigment redistribution, the development of defects and atrophy of the pigment epithelium and choriocapillary layer. As a result of these changes, a limited area appears in the field of vision, where vision is severely weakened or completely absent (central scotoma). Patients with a dry form of age-related macular degeneration may complain of double vision, decreased visual clarity near, the presence of blind spots in the field of vision.
There are several stages in the development of the exudative form of age-related macular degeneration.
- At the stage of exudative detachment of the pigment epithelium, there may be a sufficiently high acuity of central vision (0.8-1.0), the appearance of temporary unexpressed refractive errors: hyperopia or astigmatism, signs of metamorphopsy, relatively positive scotoma (a translucent spot in the field of vision of the eye), photopsia. There is a slight elevation of the retina in the form of a dome in the macular region (detachment zone), which has clear boundaries, the druses become less distinguishable. At this stage, the process can stabilize, the detachment may fit independently.
- At the stage of exudative detachment of the neuroepithelium, complaints mostly remain the same, visual acuity decreases to a greater extent, there is an indistinctness of the boundaries of detachment and swelling of the raised area of the retina.
- The stage of neovascularization is characterized by a sharp decrease in visual acuity (up to 0.1 and below) with loss of ability to write and read. Exudative hemorrhagic detachment of the pigment and neuroepithelium is manifested by the formation of a large white-pink or gray-brown clearly delimited focus with clusters of pigment, newly formed vessels, cyst-shaped retina protruding into the vitreous body. When the newly formed vessels are ruptured, subpigmental or subretinal hemorrhages are noted, in rare cases, the development of hemophthalmos. Vision is kept at a low level.
- The scar stage of age-related macular degeneration proceeds with the formation of fibrous tissue and the formation of a scar.
In the diagnosis of age-related macular degeneration, the presence of characteristic manifestations of the disease (various types of metamorphopsies, positive scotoma, photopsies) is important. A comprehensive ophthalmological examination is carried out:
- Primary diagnostics: visual acuity check, ophthalmoscopy, Amsler test for visual distortion, campimetry (studies of the central field of vision).
- Basic diagnostics. The most informative diagnostic methods for age-related macular degeneration are optical coherence and laser scanning tomography of the retina, computer perimetry, electroretinography, fluorescent angiography of retinal vessels, allowing to identify the earliest signs of damage.
- Additional diagnostics. Tests can be used to check color perception, visual contrast, and the size of the central and peripheral visual fields.
It is necessary to carry out a differential diagnosis with melanosarcoma of the choroid.
In the treatment of age related macular degeneration, medical, laser, surgical methods, electro-oculostimulation and magnetostimulation are used, which makes it possible to stabilize and partially compensate for the condition, since complete restoration of normal vision is impossible.
Treatment of dry form
Drug therapy for non-exudative form of age related macular degeneration includes intravenous, parabulbar administration of disaggregants and anticoagulants of direct and indirect action, angioprotectors, vasodilators, antioxidants, hormones, enzymes, vitamins. Laser stimulation of the retina is performed by low-intensity radiation of a semiconductor laser with a defocused red spot.
Treatment of wet form
In the exudative form of this disease, local and general dehydration therapy and sectoral laser coagulation of the retina are indicated in order to destroy the subretinal neovascular membrane, eliminate edema of the macular region, which prevents the further spread of the dystrophic process. Photodynamic therapy and transpupillary thermal therapy of the retina are also promising methods of treatment of exudative age-related macular degeneration.
Surgical treatment is vitrectomy (in non-exudative form to remove subretinal neovascular membranes), choroid revascularization and vasoreconstructive operations (in non-exudative form to improve blood supply to the retina). The visual acuity index favorable for treatment is from 0.2 and higher.
Prognosis and prevention
The prognosis for vision in age-related macular degeneration is generally unfavorable. Prevention consists in minimizing risk factors, timely treatment of ophthalmic diseases.