Congenital retinoschisis

Introduction to congenital retinoschisis Congenital retinoschisis (congenital retinaschisis) is a kind of vitreoretinaldystrophy, which is already present at birth. It is rarer than acquired retinal cleft palate. Vitreous hemorrhage and retinal detachment are the most serious complications. basic knowledge The proportion of illness: 0.002% Susceptible people: seen in young children Mode of infection: non-infectious Complications: vitreous hemorrhage retinal detachment ametropia hyperopia strabismus

Causes of congenital retinoschisis

(1) Causes of the disease

The disease is an X-type cryptic recessive disease, but autosomal recessive inheritance has also been reported. Autosomal dominant inheritance and genetic methods are uncertain. The mother is a carrier and the cleft palate is symmetrical.

(two) pathogenesis

The pathogenesis of this disease is still uncertain, there is a vitreous abnormality theory, Müller cell defect theory and retinal vascular abnormality theory, due to a congenital abnormality of the innermost layer of the retina, especially the inner end of Müller cells attached to the inner limiting membrane has some genetic defects. Or a vitreous cortical abnormality, the retina is pulled by it, leading to the division of the nerve fiber layer. This traction may be due to insufficient growth of vitreous in the normal developmental eyeball, or thickening and contraction of the vitreous during perinatal period. The vitreous body adheres to the inner wall of the eye cup. When the original vitreous body contracts, the inner layer of the retina is pulled. The lower part of the retina of the retina begins to develop in the late embryonic stage, and the blood vessels around the temporal side develop late and are distributed less once the inner layer of the retina When it is pulled, it is easy to crack around the side of the iliac crest.

Congenital retinoschisis prevention

There are no effective preventive measures for this disease.

Congenital retinoschisis complications Complications, vitreous hemorrhage, ametropia, hyperopia, strabismus

Vitreous hemorrhage and retinal detachment are the most serious complications of this disease. The incidence of vitreous hemorrhage is as high as 40%, and nearly 20% of patients have retinal detachment.

1. Retinal detachment of the hole: It can be seen that there is a hole in the outer layer of the cleft palate, a hole is formed around the cleft palate or a hole is caused by the vitreous traction. The liquid can enter the retina through the outer hole or the vitreous detachment. under.

2. Vitreous blood: The incidence of vitreous hemorrhage is 40%, usually due to the rupture of branch vessels, very few due to neovascularization, and the formation of neovascularization due to ischemia caused by microvascular lesions in the cleft palate. The blood vessels cause repeated bleeding of the vitreous, and fundus fluorescein angiography is a dye leak from the optic disc and the blood vessels surrounding the retina.

3. Other complications: Refractive is also common in patients with this disease, the incidence of hyperopia and strabismus can be as high as 29%, other rare complications are macular traction caused by vitreous traction, exudative retinal detachment, newborn Vascular glaucoma is shrinking.

Congenital retinoschisis symptoms common symptoms nystagmus pigmented spot retinal edema pigment abnormal retinal detachment fundus changes

Congenital onset, more common in male children, rare in women, often found in school-age or pre-school vision defects, when the amblyopia on the side of the eye often has a disuse exotropia, low vision in both eyes is prone to nystagmus, occasionally Spontaneous vitreous hemorrhage occurred, and was discovered only when a family was investigated by a proband.

1. Visual acuity change: The general visual acuity drops to 0.2-0.4. The visual acuity decreases with age. Finally, it can be reduced to about 0.1. In the 10 years old, the monocular or binocular vision is poor. The disease occurs in the peripheral or macular area. Significant damage, more than half of less than 0.3, the macular part of the eyesight is even worse, the majority of patients with this disease are male, female patients are parents from the family with this disease.

2. Macular cleft palate: The cleft palate occurs in the macula and is called macular retinoschisis, which causes macular abnormalities. It can be seen in all patients and may be the fundus features of the disease. Only the foveal fovea disappears in the early stage of the disease. The pigment is disordered and the stellate pigment is shed. The characteristic change is the cystic bulge around the fovea, or the fine spoke-like appearance. The central fossa develops into radial cyst-like folds, which gradually merge into doughnuts (doughnuts). The shape of the retinal palpebral fissure, the patient's macular manifestations vary, small beam-like elevation or microscopic radial folds centered on the fovea or the combination of the two is the most characteristic manifestation, in some patients with extensive retinal High, almost occupying the entire posterior pole, surrounded by large blood vessels, the macula abnormalities may be very small, and the superficial radioactive folds are almost invisible through the slit lamp. The use of red light missing light helps to observe, in a certain Some patient pigment spots may be the only change, while in others, the foveal reflex disappears may be the only macular abnormality. Changing elderly patients are often overlooked and are considered to be age-related normal changes.

3. Peripheral retinal palpebral fissure: The incidence of peripheral cleft palate seen by ophthalmoscope is 71%-85%, and the cleft palate in the peripheral part is mainly classified into two types: one is a flattened surface such as a variegated shape, which occurs mostly above the fundus. In the larger children or adults, due to the spontaneous degeneration of the vesicular retinal palpebral fissure in early childhood, the other type is the giant vesicle of the retina, which is more common underneath. It occurs in boys under 4 years old and can spread over the cleft palate. The anterior wall generally does not exceed the serrated edge. The inner wall of the giant vesicle can be a large hole. The most characteristic lesion outside the macular area is a spherical elevation of the inner layer of the retina with a large ort hole or holes. Many chapped spheres, low flat ridges, usually evident in the equator, sometimes extending backwards or even close to the optic disc, the color of the blood vessels in the low flat ridges is dark, and the projection of blood vessels on the choroid is visible, if there is no corresponding area Functional impairment, indicating that there are still most intact optic nerve fibers and synapses in the cleft palate, occasionally in the separation zone of two spherical cleft palate in one eye, the premature lesion rarely spreads to the serrated margin, and the posterior border often bulges. Moreover, in the disease, the inner layer of the hole is larger and more likely to occur than the outer layer of the hole. The disease occurs in the nerve fiber layer, the superficial layer of the retina, the outer layer of the retina is gray-like transparent, and the outer layer is relatively rare. And even if it is small, it is difficult to see, often round, and close to the cleft edge of the cleft. If it occurs at the same time, the outer hole can also cause retinal detachment.

Along the posterior border of the retinal cleft palate, white or pigmented dividing lines are common, which may be caused by the pulling stimulation of the RPE along the posterior cleft palate, and the retinal vessels are generally located on the inner layer of the cleft palate. However, it can also be seen that the blood vessels move from the inner layer to the outer layer, and white sheaths are often seen on the blood vessels in the cleft palate.

4. Vitreous lesions: The vitreous changes of the disease are atypical fibril condensation, vacuolization formation, post-separation and concentration, early vitreous cortex is dense, still covering the cleft palate, the vitreous has no posterior detachment, cleft palate A hole is also visible in the inner layer, indicating that the hole is not caused by the vitreoretinal retraction but due to tissue degeneration, but then extensive internal stenosis, often accompanied by posterior vitreous detachment and concentration, occasionally, a small piece of vitreous cortex remains Retinal blood vessels adhere and pull, and also lead to vitreous hemorrhage, this glass volume of blood, mostly located in the posterior vitreous cavity and retinal palpebral cavity, and often can be absorbed faster, vitreous hemorrhage is common in young patients, in this disease During the period of development, less frequent after 20 years of age, long-term bleeding can form yellow, bleeding in the vitreous mechanization, contraction and traction, can produce full-thickness retinal tears and fixed retinal folds, vitreous hemorrhage can be the first disease Performance, in the late stage of the disease, the entire inner layer disappeared, the retinal blood vessels were invisible, the outer layer was degenerated, a large number of pigmented spots appeared, and pigmentation Fundus retinal blood vessels of the lower half and no male patients should consider this disease, until diagnosed as other diseases.

In addition to vitreous changes, there are still vitreous membranes whose properties are not known. They are abnormal tissues located between the inner limiting membrane and the vitreous. The membrane is translucent and often adheres to the optic disc and the retina, and some or all of the membranes are free. However, there is often a certain adhesion at the equator, usually adhering to the inner layer of the spherical bulge at the lower part of the cleft. On the adhesion line, the retinal blood vessels are bent at an acute angle, and the inner retina is deformed, even the general ophthalmoscope is difficult. When the retina of the cleft palate is seen, the membrane on the optic disc leads to pseudo optic disc edema. The normal retinal blood vessels of the sacral disc involve the optic disc toward the temporal side, similar to the mild lens after the fiber proliferation, glass film or machined glass. The volumetric blood can cause ectopic macular ectopic, sometimes the neovascularization originating from the optic disc can be seen on the vitreous membrane, sometimes on the inner layer of the cleft palate. This vitreous membrane may be fused with the cleft palate, and the vitreous membrane is The signs of peripheral fundus traction can be expressed as map-like oppression and whitening.

5. Other fundus changes: The retinas that have not been invaded around the fundus have grayish white or silvery white degeneration. In severe cases, there are silver foil-like sparkling reflections, retinal edema-like changes, occasional peripheral retinal neovascularization, and choroid in advanced cases. Atrophic or old chorioretinitis-like pigment abnormalities, sometimes with pseudo-opic discitis, may be due to glial tissue hyperplasia.

Examination of congenital retinoschisis

1. Genetic examination: The gene of this disease has been mapped to the distal end of the short arm of the X chromosome, especially Xp22.1-p22.2. Although the disease has changes in the fundus, there is no evidence on genetic heterogeneity. A literature on improving the mapping of genetic maps in the RS region has been reported. A study by a Finnish patient reported that the RS critical region has been narrowed to 0.2-0.3 cm, between the markers DXS418 and HYAT1, accompanied by ophthalmoscopy and ERG examination. DNA-based diagnosis contributes to heterozygous carriers of the disease, and can also be used for early diagnosis of sick infants. The genes associated with this disease have been identified and considered as XLRSI (X-linked retinoschisis I The mutation causes a disease in men.

2. Histopathological examination: Under the photoelectric microscope, the retinal cleft palate is located in the retinal nerve fiber layer and the retinal ganglion cell layer. The retina mainly splits along the glial cells and the nerve fiber layer to form a cleft palate cavity. The retinal tissue extends, and the inner layer of the cleft palate is mainly composed of internal limiting memberane, part of Müller cells and vascular tissue. These collagenous tissues are thickened in the vascular part of the retina, and the outer layer of the cleft palate contains the inner granular layer. The outer granular layer, the outer plexiform layer and the susceptor cell layer, the outer layer is thickened by gliosis, and in the cleft palate region, intact glial cells and nerve fiber layers are usually not obvious, but bipolar cells and photoreceptor cells The layer is intact, the inner granular layer tends to be thin, but it can be double-layered, the inner layer of the retina becomes thicker and the structure is disordered. The inner layer of many cleft palate, the outer layer and the retina adjacent to the cleft palate cavity are found to have a large amount of eosinophilicity. The composition of amorphous material, the presence of filamentous material in the extracellular space adjacent to the inner and outer layers of the cleavage cavity by transmission electron microscopy, the experiment proves that the filament is light The amorphous substance seen below, Gottinger observed that in patients with peripheral retinal vesicle degeneration and senile retinoschisis, the same extracellular filaments with cross-striped 8-12 nm diameter, but these filaments and glass The acid-sensitive mucopolysaccharide develops a color reaction that is different from that found in Gondon's patients with cleft palate.

The eyeball removed from the disease was studied. It was found that the hole appeared in the optic nerve fiber layer, and the periodic amorphous substance was visible in the retina. Under the ultrastructure, the amorphous substance consisted of filaments with a diameter of 11 nm, and the filament inside the retina was Due to defects in Müller cells, these extracellular accumulations cause degeneration of these cells and subsequent cleft palate, and glial fibrillary acidic protein and possibly S100 protein produced by defective Müller cells accumulate. In the retina.

3. Fluorescence angiography: It can be seen that there are dilated capillaries and fluorescent spots in the fovea of the macula, indicating that there is atrophy of the pigment epithelium, but there is no typical leakage. In the macular cleft plaque, no dye leakage to these cystic areas This is clearly different from microcystic macular edema, where significant telangiectasia, peripheral vascular curling, and abnormal vascular traffic are visible at the junction of the peripheral retinal cleft palate and the normal retina. These dilated and abnormal blood vessels have significant fluorescein leakage. To form a strong fluorescent region locally, indicating that there is a change in vascular permeability.

4. Optical coherence tomography (OCT): The OCT image of this disease shows a typical cystic change of the macula, with oblique or vertical bridge-like tissue connected, and the posterior pole retinal neuroepithelial layer is separated, with a bridge between them. The OCT images of the membranous tissue changes are the inner neuroepithelial thickening and the outer neuroepithelial separation. OCT is highly specific for retinoschisis and clearly shows retinal neuroepithelial separation.

5. Vision: This disease often has a relative central dark spot. The central area of the macular retinal palpebral fissure can have a small annular dark spot. The low-level retinal palpebral fissure region is often difficult to detect visual field defects due to the two layers in the cleft palate. There is still a nerve fiber connection between them.

6. Electroretinogram (ERG): In this disease, ERG examination has characteristic and diagnostic significance. Because the fundus of retinal cleft palate shows multiple forms, it may be difficult to diagnose according to fundus examination. In this case, ERG can Auxiliary diagnosis, the b-wave amplitude shows a disproportionate decrease compared with the a-wave, which is a characteristic of this disease. In the early stage of the disease or in mild illness, the possibility of b-wave amplitude drop with swing and no change of a-wave can be observed. The ratio of b-wave to a-wave amplitude is reduced to a greater extent. Because ERG is an integrated response, abnormal ERG indicates that the macular peripheral retinal diffusivity is affected, even in cases of visible abnormalities of the macula. When the disease progresses and the receptor is degenerated, the amplitude of the a wave becomes smaller. However, the amplitude of the b wave decreases, so the ratio of the b/a amplitude is usually maintained. When the retinoschisis is more advanced and the fundus exhibits a wide range of pigments. When the retinal blood vessels in the lower part of the group and the lower part of the fundus or the wider area disappear, the b wave of the ERG can completely disappear, leaving only the small a wave or PIII component. With the further development of the disease, the a wave also disappears, making the ER G was not recorded at all, and the ROG of the macula also showed a low b/a amplitude ratio with the possibility of reducing the swing. In cases of macular degeneration, the macular ERG could not be recorded.

The ERG of this disease has characteristic changes, which is helpful for the diagnosis of this disease. The amplitude of ERG a wave is normal, b wave is more than d wave, so the ratio of a and b wave (b/a) is often smaller than normal, with a relatively high ERG was recorded under white light stimulation. The b wave was often lower than the baseline. Even in the macular area, the b wave was not normal. When the fundus was extensively affected, the a wave and the b wave were small, and the b/a ratio was still low. In the development of the affected eye, the b wave is severely reduced to unrecordable, leaving only the small a wave. The most severe cases are not detected even with the a wave. The ERG is completely unrecordable, the OPs wave is significantly reduced or disappeared, and the absolute threshold test (absolute threshold) Profile) can compare the normal control eye and retinal palpebral eye with multifocal ERG in the normal range, and the average response density or latency of the 6 annular retinal areas in the control group and the retinal cleft palate All showed that the difference was very significant. The multifocal ERG three-dimensional images of patients with retinal cleft palate showed multiple local amplitude reductions, and the central peak response disappeared or decreased. The P1/N waves of the reaction density values of the six annular retinal regions Ratio is different from all The b/a ratio of the visual field ERG and the multifocal ERG three-dimensional image of the retinal cleft palate patients showed multiple local amplitude reductions, which were related to the local functional damage caused by the presence or rupture of multiple small cysts in the macular area of the patient. A distinctive change in the disease.

In the early or mild cases of this disease, when ERG has been significantly depressed, dark adaptation, absolute threshold of rods and cones, only minor damage, female heterozygous carriers usually check for ophthalmoscope and electroretinogram However, there is an inner limiting membrane wrinkle near the fovea, or a degeneration of the peripheral retina and hyperglia similar to that of a male patient, but most of these abnormalities appear to be non-specific and non-uniform.

7. Electro-oculogram (EOG): The ratio of light peak/dark valley in the EOG of this disease remains normal until the most advanced stage, and the EOG light peak can be seriously damaged. The results of ERG and EOG test indicate that at the beginning of the disease, the photoreceptor function is still The preservation is good, the inner layer of the cleft is abnormal, and the photoreceptor is affected after a period of time.

8. Dark adaptation: The patient's dark adaptation to the middle cone, the threshold of the rod is increased, and even the macular retinal palpebral fissure is also changed.

Diagnosis and diagnosis of congenital retinoschisis

Diagnostic criteria

1 The patient's starting age is small;

2 There is a transparent gauze-like membrane bulging from the inner layer of the retina, and sometimes there are large holes in the inner layer accompanied by retinal blood vessels;

3 abnormalities of the macula, cystic degeneration, atrophy and pigmentation;

4 after the vitreous body is detached;

5 severe visual impairment is due to macular degeneration, vitreous hemorrhage and retinal detachment;

6 field of view is often a defect above the nose;

7X sex-linked recessive inheritance, the diagnosis mainly depends on the genetic characteristics of the disease and auxiliary examination, clinically based on typical clinical manifestations and familial morbidity, using direct or indirect ophthalmoscopy, electrophysiological features, fluorescent angiography and other tests can basically be determined Diagnosis, in addition, OCT can effectively distinguish between the macular hole and the foveal fovea, which can obtain a cross-sectional image of the retinal tissue structure in vivo, clearly showing the fine structure of the inner and outer layers of the retina and objectively, quantitatively measuring, analyzing, and retinal thickness. The analyzer (RTA) determines if the splitting occurs between the layers of the retina and the size and shape of the split.

Differential diagnosis

Primary retinitis pigmentosa: there is no significant difference between the clinical features of congenital retinoschisis and retinitis pigmentosa, extensive pigmentation with retinal vascular stenosis, unrecordable ERG with complete night blindness, ERG can help identify if recordable The a wave is accompanied by the disappearance of the b wave, and congenital retinoschisis can be considered.

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