Which Are the Most Common Macular Degeneration Causes?

The pathological mechanism of macular degeneration is mainly the aging change of the macular structure. It appears that the retinal pigment epithelium has reduced phagocytosis and digestion of the outer disc membrane of visual cells, leaving undigested disc membrane corpuscles to remain in the basal cell original paddles, and excreted outside the cell, forming a glass membrane wart, so secondary After pathological changes, macular degeneration occurs, which is mainly related to long-term chronic light damage in the macular region, choroidal vascular sclerosis, and retinal pigment epithelial cells aging.

Western Medicine Name: Macular degeneration
Affiliated Department: Department of Ophthalmology-Ophthalmology
Disease site: Eye
The main symptoms: Vision loss

Main cause: Degenerative
Multiple groups: Middle-aged and elderly
Contagious: Non-contagious
Whether to enter health insurance: Yes

Introduction to macular degeneration

Macular degeneration is usually the natural result of aging. As the age increases, the retinal tissue degenerates and becomes thinner, causing macular function to decline. In 10% of patients with macular degeneration, the microvasculature responsible for supplying nutrients to the retina will leak and even form scars. New abnormal blood vessels are also common. Leakage of blood vessels will damage the macula and cause vision distortion. , Vision loss, dense scars cause a significant decrease in central vision, affect quality of life, and even become blind.

Macular degeneration Sometimes macular degeneration can also be caused by trauma, infection or inflammation, and there are certain genetic factors for the disease.

In western countries, macular degeneration is the leading cause of blindness in people over 50 years of age. In the United States, macular degeneration causes more blindness than the combined number of blindness caused by glaucoma, cataract and diabetic retinopathy.

The incidence of macular degeneration is not low in China, with a incidence of 6.04% -11.19% at the age of 60-69. With the accelerated aging of China's population, the disease has a clear upward trend, but the general people's awareness and concern about macular degeneration are not enough.

At present, the etiology of macular degeneration is not fully understood, and the treatment method is still to be studied and developed. Patients can pay attention to new therapies for the disease. At the same time, remind senior friends to pay attention to eye health and establish the concept of regular eye examination.

Macular degeneration disease types

There are two types of age-related macular degeneration and juvenile macular degeneration:

Age-related macular degeneration

Age-related macular degeneration, also known as age-related macular degeneration (AMD). This disease mostly occurs in people over 45 years of age, and its prevalence increases with age. It is an important blinding disease for middle-aged and elderly people. So far, no exact and effective drug therapy has been found in modern medicine that can prevent the progression of the disease.

Clinical manifestations of macular degeneration

The atrophy and exudative type of this disease are as described above, and some people have observed that atrophy can be converted into exudative, so it is considered necessary to type. However, in most cases, the clinical manifestations are very different from the prognosis of type II.

Atrophic senile macular degeneration

Atrophy is also called dry or non-exudative. Both eyes often develop simultaneously and develop simultaneously. It has the same clinical history and manifestations as senile hereditary macular degeneration (that is, Haab disease). Whether they are the same disease, because both occur in the elderly, family investigation is difficult and difficult to determine. This type is characterized by progressive pigment epithelial atrophy, which is clinically divided into two phases:

1. Early stage (preatrophic stage): The central vision is slightly damaged, and it remains normal or close to normal for a long time. The visual field can detect dark spots at the center of 5 to 10 °. It is easier to detect with blue and yellow visual targets. The 180 ° line static visual field examination showed a decrease in visual sensitivity at 5 to 10 ° on each side. The Amsler grid chart is often positive. Occasionally large or small vision.

Under the ophthalmoscope, the macula has dense dense dura warts. Warts vary in size. Some are fused into small pieces. Between the glass membrane warts, there is a bit of flake pigmentation and pigmentation, and the appearance is pepper and salt. This lesion is centered on the central fossa and is gradually inspected around. There is no clear boundary on the edge. In some cases, the entire macula was darkly stained. A slit lamp microscope and a front mirror were used for light section examination, and a slight halo (lantern phenomenon) was observed in and around the slight elevation. It is suggested that there is shallow detachment in the upper layer of the pigment, and the fluorescent spots at this stage strengthen quickly. The intensity is greatest within one minute after the start of the venous phase, and most of the time it is consistent with the background fluorescence, it rapidly weakens and gradually disappears. In a few cases, fluorescence obscuration can still be seen after the background fluorescence subsides. In patients with shallow detachment of pigmented epithelial layer, circular or quasi-circular fluorescent spots appeared in the early stage of angiography. Fluorescence spots do not enlarge, indicating that there are no new blood vessels under the pigment epithelium, or although they are thin, they are not sufficient for visualization (concealed new blood vessels).

2. Late stage (atrophic stage): the central vision is severely impaired, and there is a virtual absolute central dark spot. There are dense or fused glass warts and large areas of light gray atrophy under the ophthalmoscope. The state of the atrophy zone became clear, with pepper and salt-like spots scattered throughout it, and beaten bronze appearance was also seen. The early atrophy of the fluorescein contrast shows strong fluorescence, and it fades out as the background fluorescence weakens and disappears. The fluorescein spots did not enlarge throughout the imaging process, suggesting that the fluorescence was caused by atrophy of the pigment epithelium. However, in some cases, strong fluorescent spots and weak fluorescent spots appeared at the same time in the atrophic area, indicating that in addition to atrophy of the pigment epithelium, choroidal capillaries atrophy and occlusion. Atrophic degeneration has a slow onset and a lengthy course. The transition between early and late stages is difficult to separate. In addition, individual differences are large, so the length of time from early to late varies, but the degree of lesions in the fundus of both eyes is basically symmetrical.

Exudative age-related macular degeneration

Exudative is also known as wetness, which is referred to as senile disciform macular degeneration by Kuhnt-Junius. This type is characterized by active neovascularization under the pigment epithelium, which causes a series of changes in exudation, bleeding, and scarring. There are three clinical stages.

1. Early (predisciform stage): Central vision is significantly reduced, and the degree varies depending on whether the central fossa is involved. Amsler grid chart was positive. A dark spot in the center can be detected corresponding to the lesion.

The macular area under the ophthalmoscope has dense, different-sized glass membrane warts, which are mainly soft and fuse with each other. At the same time, pigmented spots and depigmented spots are seen from time to time. Some pigmented spots are round and halo around the glass membrane wart, and the central fossa is dim or disappears. At this time, fluorescein angiography: the glass warts and depigmentation showed fluorescence early, and its enhancement, attenuation, and disappearance were synchronized with background fluorescence. In some cases, there are still strong fluorescent spots after the background fluorescence disappears, indicating two cases: one is the staining of the glass membrane wart; the other is the existence of new blood vessels under the pigment epithelium. Distinction between the two: the former enlarges the fluorescent spot during the whole process, while the latter does the opposite.

2. Middle stage (evolutionary stage): This stage is mainly characterized by the formation of pigment epithelium and / or neuroepithelial serous or hemorrhagic detachment due to leakage of new blood vessels in the macula. Vision drops sharply. In addition to the aforementioned early changes under the ophthalmoscope, a wide range of round or round-shaped lesions with a dark color and a slight bulge make the entire lesion area appear dark and mottled. In some cases, the murmur has dark red bleeding spots. Slit-lamp microscope and front-end light section examination showed serous exudation under the cortex on the pigment and / or under the neuroepithelium. The bleeding position is also the same. The lesions developed further, with yellow-white exudation deep in the retina. Some exuded are uniform plaques; some are cluster-shaped spots of different shades; some are located inside the lesion; some are around the edge of the lesion and are irregularly ring-shaped or crescent-shaped (Coats reaction). When the bleeding is severe, it can lead to dark red or even brownish brown hematomas under the pigment epithelium or neuroepithelium; sometimes it spreads to the nerve fiber layer and there are flame-like bleeding spots; it can also penetrate the inner boundary membrane into the vitreous body, forming glassy blood. Early in the fluorescein angiography, mottled fluorescence was seen in the lesion area, and lace-shaped or wheel-shaped fluorescence appeared immediately, suggesting the existence of active neovascularization. After that, the fluorescence continued to diffuse and increase. About to the venous phase or later, the entire detachment cavity was filled with fluorescence. The clearer outline was pigment epithelial detachment; otherwise, it was neuroepithelial detachment. Such strong fluorescence from the cavity persists after the background fluorescence disappears. The fluorescence from the cavity is generally uniform, but when accompanied by pigment hyperplasia or bleeding, there is corresponding fluorescence shielding. Those with severe rupture of new blood vessels and the formation of hematomas seen under the ophthalmoscope mentioned above appear large areas of fluorescent shielding. At the end of the angiography, sometimes one or two fluorescent spots (called hot spots) that gradually increase and enlarge may appear in such a fluorescent shielding area to prove the existence of new blood vessels under the retina.

3. Late stage (reparative stage): Exudation and bleeding gradually collect and are replaced by scar tissue. Vision is further impaired. Fundus examination showed slightly elevated lumps or irregular white plaques (red and yellow during hematoma absorption). The plaque is located below the retinal blood vessels. Bleeding spots and pigmented spots are often seen on the plaque surface or its edges. In some cases, when the bleeding and exudation were replaced by scars, the lesions did not end there, but new neovascularization appeared at the edge of the scar, and they again experienced the process of exudation, bleeding, absorption, and scarring. Repeatedly, the scar is further enlarged. Therefore, long-term follow-up observation of such patients is necessary. As seen in this phase of fluoroscopy, light-colored scars are falsely fluorescent; fluorescence is obscured at the hyperplasia of the pigment; if there are new blood vessels at the edge of the scar or between the scars, and exudation and bleeding, there are gradually enlarged fluorescent spots. Exudative age-related macular degeneration occurs in both eyes, and the interval is usually not more than five years.

Macular degeneration pathogenesis

The specific pathogenesis of macular degeneration has not been fully understood, and hypotheses have been proposed including: genetic factors; light accumulation damage; free radical damage; hemodynamic factors.

Recently, research has proposed that the theory of susceptibility to rod cells is composed of a foveal region dominated by cone cells and a parafocal region dominated by rod cells. The highest density of rod cells is in the area of 4 to 6 ram from the fovea. The degeneration of rod cells and cone cells is the basic feature of aging and macular degeneration in the elderly. In the donor eye with a normal macula, the number of concavity cone cells was basically stable, while rod cells decreased by 30% in adulthood. Histopathological examination revealed a persistent decrease in rod cells in early age-related macular degeneration.

Macular degeneration Among them, the largest decrease was 1 to 3 mm from the fovea (3.5 to 10 degrees from the fixation point). A large number of cone cells were found on exudative senile macular degeneration disc scars. Pigment epithelial cell deposits are drastically reduced. Recent studies on the elderly and early age-related macular degeneration patients have shown that their scotopic sensitivity decreases more significantly than that of photopic vision. Before the RPE / Bruch's membrane complex became diseased, the photoreceptors had undergone degeneration and reduction. Psychophysics Both histopathology and histopathology revealed that rod cells are more susceptible than cone cells.

Studies on retinal pigment degeneration suggest that a diffusible substance produced by rod cells affects the survival of cone cells. Although the specific mechanism is not clear, it suggests that the selective vulnerability of concave spectacle cells in elderly macular degeneration centers may be a new pathogenesis. In the same clinical stage, patients with rod cells and cone cells have different loss performance. It also shows that macular degeneration in the elderly is a group of disorders with allogenic mechanisms.

Macular degeneration disease harm

Macular degeneration is a chronic eye disease that can cause a sharp decline in central vision, which is necessary for daily activities such as reading, looking at time, recognizing facial features, and driving. It is an irreversible decline or loss of central vision that is difficult to cure. Age-related macular degeneration occurs more than 45 years of age. The older the age, the higher the incidence. The incidence is racially different, with whites having a higher incidence than people of color.

Macular degeneration belongs to the category of "seeing faintness" and "violent blindness" in Chinese medicine. Due to the limitations of conditions and diagnostic techniques, the disease has not been thoroughly explored. In recent years, many ophthalmologists have carried out a lot of clinical research work in this area, and have a complete understanding of the etiology and pathogenesis of TCM and the laws of different stages of the disease.

Diagnosis of macular degeneration

The age of onset is over 45 years. The older the age, the higher the incidence. The eyes develop successively. It is one of the main eye diseases of visual impairment in the elderly.

Central vision slowly declines, there may be distortion of vision, there is fixation shadow in front of the eyes, and eventually central vision is lost. Peripheral vision is present.

(3) Fundus examination:

Dry type: pigmentation disorder in the macula area can be seen in the early stage, the fovea is not clear, and there are scattered glass warts. In the late stage of the onset, the macular area may have metal-like reflections, and the retinal pigment epithelium atrophy shows a map-like shape, showing cystoid degeneration.

Wet type: There are many fusions of glass warts with unclear borders, macula with dark black graphics, or irregular lesions. The range of bulges can be 1-3 PD. A large amount of subretinal hemorrhage can enter the vitreous body and form vitreous hemorrhage. The late lesions were grayish white scars.

Fundus fluorescein angiography shows atrophy of the retinal pigment epithelium when there is visible fluorescence. There may be masking fluorescence in the pigmentation, lace-like or reticular neovascularization in the early stage, and fluorescein leakage (wet type) in the later stage.

First, age-related macular degeneration

It appears that the retinal pigment epithelium has reduced phagocytosis and digestion of the outer disc membrane of visual cells, leaving undigested disc membrane corpuscles to remain in the basal cell original paddles, and excreted outside the cell, forming a glass membrane wart, so secondary After pathological changes, macular degeneration occurs, which is mainly related to long-term chronic light damage in the macular region, choroidal vascular sclerosis, and retinal pigment epithelial cells aging. Macular degeneration is divided into atrophic and exudative types according to different clinical manifestations:

atrophic type-also known as dry or non-exudative

It is mainly atrophy of choroidal capillaries, thickened membrane and retinal pigment epithelium atrophy.

Exudativealso known as wet or discoid macular degeneration

It is mainly the destruction of the glass membrane. Choroidal blood vessels invade the retina to form choroidal neovascularization, and the serous or hemorrhagic discoid detachment of the retinal pigment epithelium or neuroepithelium in the macular region occurs, and eventually becomes an organic scar. Can be transformed into exudative type.

Second, juvenile macular degeneration (Stargarde) is also called congenital macular degeneration.

Most of them start at the age of 8-14, and they are autosomal recessive eye diseases. The cause is related to lipid deposition in retinal pigment epithelial cells. Due to the degeneration of these cells, macular choroid and retinal atrophy.

Diagnosis points and clinical manifestations:

In the early stage of iliac lesions, the fundus is completely normal, but the central vision has been significantly reduced, which is easily misdiagnosed as amblyopia or rickets. Lesions progress slowly, but are symmetrical and progressive, and typically show typical changes around the age of 30, with central vision dropping to 0.1 or lower.

Fundus examination: When the visual acuity of the patient's center is decreased, the macular lesions are often not significant, and the two are disproportionate; subsequently, the foci of the macular foci disappear, and uneven pigment spots appear, which are gray reflective, and eventually the macular degeneration is detached from the pigment circle. Area with gold leaf-like reflections. The choroid becomes white, the blood vessels become thinner, and the optic disc is pale.

(3) Before the fundus changes appear, fluorescent angiography can show high fluorescence in the macular area.

Electrophysiology, EOG decreased slightly, ERG showed that the cone function was gradually lost.

Macular degeneration disease treatment

So far, whether it is macular degeneration in the elderly or macular degeneration in the juvenile, there is no definite drug treatment in modern medicine, and no good method to prevent the progress of the disease has been found. So far, the treatment is still very difficult.