Crystal dislocation

Introduction to crystal dislocation Under normal conditions, the lens is suspended from the ciliary body by a crystalline suspensory ligament whose axis is almost identical to the visual axis. Defects or rupture of the suspensory ligament of the crystal due to congenital, traumatic or pathological causes may cause a decrease in suspension force, resulting in ectopialentis or subluxation; if the suspensory ligament is completely broken, complete dislocation of the crystal may occur. The treatment of crystal dislocation is difficult because the removal of dislocated crystals is more risky than general cataract extraction. Blind surgery may lead to visual impairment or even loss of the eyeball. Therefore, the treatment plan should be carefully decided. The treatment of crystal dislocation depends on the position of the crystal. The hardness of the crystal, the visual acuity of the eye and the visual acuity of the contralateral eye, age, presence or absence of congenital abnormalities, presence or absence of complications and surgical conditions. basic knowledge The proportion of sickness: 0.0003%-0.0008% Susceptible people: no specific population Mode of infection: non-infectious Complications: vitreous ridge retinal detachment retinopathy

Cause of crystal dislocation

Congenital crystal ectopic or dislocation (15%):

Can be used as a congenital anomaly to occur alone; or with pupillary ectopic and other ocular abnormalities; or with mesoderm, especially systemic syndrome of bone dysplasia, in any case, due to the weakness of a part of the crystalline suspensory ligament, The force of the traction crystal is asymmetrical, causing the crystal to shift in the opposite direction of the poorly developed suspensory ligament.

Traumatic lens dislocation (25%):

Eye trauma, especially ocular contusion, is the most common cause of dislocation of the lens. Traumatic dislocation of the lens is often accompanied by secondary cataract formation. Dislocated crystals can be detached into the anterior chamber or vitreous cavity; The eyeball is broken and the crystal can be removed under the bulbar conjunctiva.

Spontaneous crystal dislocation (8%):

Spontaneous lens dislocation is caused by mechanical lesions of the suspensory ligament caused by intraocular lesions, or due to inflammatory decomposition and degeneration. Crystal dislocation due to mechanical elongation of the suspensory ligament is common in bulls eye, grape swelling or eyeball expansion. Ciliary body inflammation adhesion or vitreous cord pulls the crystal, the intraocular tumor can push and pull the crystal away from the normal position, the inflammation destroys the crystal suspensory ligament can be seen in endophthalmitis or total ocular inflammation, the suspensory ligament can be completely decomposed, long-term chronic ciliary body inflammation The same pathological process can occur. The suspensory ligament can be occupied by the granule tissue of the ciliary body. Degeneration or malnutrition of the suspensory ligament is the most common cause of natural dislocation, often accompanied by degeneration and liquefaction of the vitreous, such as high myopia, old choroid Inflammation or ciliary body inflammation, retinal detachment, iron or copper rust, etc. can also gradually degenerate the suspensory ligament, another common cause is the over-mature period of senile cataract, crystal degeneration changes also involve the lens suspensory ligament, once Degeneration of the suspensory ligament, the crystal can spontaneously dislocate at any time due to its own weight or slight trauma or even force and cough

When the crystal is dislocated, the broken suspensory ligament can be connected with the lens and gradually become turbid. The suspensory ligament is rarely broken at the end of the ciliary body, and most of it is broken at the end of the crystal plate, so that the suspensory ligament can be found in the dislocated crystal. There are few opportunities.

Abnormal crystal position can be caused by congenital dysplasia. If the crystal is not in the normal position after birth, it can be called crystal ectopic. If it is born due to congenital factors, trauma or lesion changes the crystal position, it can be collectively called lens dislocotion. Or partial sublaxation, but in the case of abnormal congenital crystal position, it is sometimes difficult to distinguish when crystal position changes occur, so there is no strict demarcation of crystal dislocation or ectopic, and it is often used.

(1) Simple crystal ectopic

There is a clear genetic predisposition, regular or irregular autosomal dominant inheritance, a few are autosomal stable inheritance, often bilateral symmetry, may be associated with fissure-like pupillary deformity, and the cause of dysplasia of the suspensory ligament is unknown. Although intrauterine inflammation, ciliary body atrophy of neuroectodermal is a possible factor, but the exact mechanism is unknown, if accompanied by ovarian dysplasia and other abnormalities in mesodermal development, it may be related to mesodermal developmental disorders. .

(B) accompanied by crystal morphology and eye abnormalities

Commonly there are microspherophakia, coloboma of the lens, and anuridia.

(c) accompanied by congenital crystal ectopic or dislocation

1. Marfan syndrome is an irregular autosomal dominant genetic disease, which is a widespread disorder of the whole body mesodermal tissue, characterized by abnormalities in the eye, cardiovascular and skeletal systems. Marfan first reported in 1896, abnormal eye manifestations. For crystal ectopic, especially the upward and lateral displacement of the iliac crest, due to the absence of the iris pigmentation layer, the posterior transillumination test may be positive, and the localization of the pupillary large muscle may make it difficult for the drug to dilate the pupil. In addition, the eye may also be There are abnormal anterior chamber angles, choroidal and macular defects, glaucoma, retinal detachment, nystagmus, strabismus, amblyopia and other complications. Skeletal abnormalities are found in the limbs of the limbs, slender, long head and long face, the heart oval hole is not closed Aneurysm and aortic stenosis are more common in men than in women.

2. Homocystinuria is an autosomal recessive disorder that most commonly affects bone. It is characterized by osteoporosis and systemic thrombosis. The crystal is dislocated under the nose and the crystal is easily removed. In the anterior chamber and vitreous cavity, the structure and ultrastructure of the crystalline suspensory ligament have abnormal changes. The eye can also be combined with congenital cataract, retinal detachment and degeneration, no iris and other abnormalities. Laboratory tests can detect bleeding, and urine contains Homocystinuria, the cause of this disease is the lack of desulfurized ether synthase, can not cause the conversion of homocysteine to cystine.

3, Marchesani syndrome is an autosomal recessive genetic disease, short body, limb finger (toe) short and thick, normal cardiovascular system, crystal spherical, less than normal, often dislocated to the lower part of the nose, crystals into the anterior chamber after dislocation, prone to occur Glaucoma, often accompanied by refractive high myopia, other eye abnormalities have ptosis, nystagmus, small cornea and so on.

Crystal dislocation prevention

Avoid eye trauma.

The intraocular pressure should be reduced with a carbonic anhydrase inhibitor or a hypertonic agent before surgery, and the Flieringa ring can be pre-sewed during surgery.

Care must be taken during surgical removal of the crystal to minimize loss of the vitreous.

Complication of crystal dislocation Complications Vitreous retinal detachment retinopathy

In addition to severe refractive errors, crystal dislocation often produces some serious complications.

First, uveitis

It is a common complication of dislocation of the lens. There are two kinds of uveitis caused by dislocation of the crystal. One is that the uveal tissue is caused by the mechanical stimulation of the crystal, and the other is that the dislocated crystal becomes the over-maturing cataract. Crystal allergic uveitis, both uveitis are intractable inflammation and can lead to secondary glaucoma.

Second, secondary glaucoma

It is also one of the most common complications. Crystals are inserted into the pupil area or the vitreous is incarcerated in the pupil, which can produce pupillary block glaucoma. Repeated pupillary block can cause the iris to swell, produce aphakic ocular malignant glaucoma, long-term crystal Dislocation can produce crystal-soluble glaucoma. In addition, the dislocation of the lens caused by blunt contusion of the eye can be combined with the retreat of the iris root, and the lateral angle of the glaucoma produces secondary glaucoma.

Third, retinal detachment

It is the most common and serious complication of dislocation of the lens, especially in eyes with congenital anomalies, such as Marfan syndrome, even for binocular, the treatment of retinal detachment caused by dislocation of the lens is difficult, because the dislocation of the crystal often hinders the search for retinal tears. The exact location and extent of retinal detachment, if the crystal is removed first, the vitreous body will be lost, the retinopathy will be aggravated, and the time of retinal detachment surgery will be delayed.

Fourth, corneal opacity

In recent years, it has been noted that dislocation of the lens can cause corneal opacity. Crystal dislocation enters the anterior chamber and contacts the corneal endothelium, leading to corneal endothelial cell damage, which can cause corneal edema.

Symptoms of crystal dislocation common symptoms complex vision membrane ulcer tremor myopia astigmatism

According to the degree and shape of crystal dislocation, it can be divided into incomplete dislocation of the crystal and complete dislocation.

First, the crystal is not completely dislocated

The displaced crystal is still in the pupil area. In the vitreous cavity of the posterior plane of the iris, the symptoms caused by incomplete dislocation of the crystal depend on the degree of crystal shift. If the axis of the crystal is still on the visual axis, only the relaxation of the suspensory ligament occurs. Crystalline myopia caused by increased curvature, if the crystal axis is horizontal, vertical or oblique tilt, can lead to severe astigmatism difficult to correct with glasses or contact lenses, more common incomplete dislocation is the longitudinal shift of the crystal, can appear monocular Double vision, eye slit lamp examination showed deep anterior chamber, iris tremor, crystal gray, visible equator or even broken suspensory ligament, vitreous hemorrhoids can be detached into the anterior chamber, the surface is pigmented; under the ophthalmoscope can be seen crescent Fundus reflex and double-eye image.

Second, the crystal is completely dislocated

The displaced crystal completely leaves the pupil area and the crystal can be displaced or produced:

(1) The pupil is incarcerated;

(2) The crystal is detached into the anterior chamber;

(3) The crystal is detached into the vitreous cavity, floating on the vitreous body or sinking into the vitreous body;

(4) The crystal penetrates into the space under the retina and the space under the sclera through the retinal tear;

(5) The crystal is perforated through the corneal ulcer, and the scleral rupture hole is inserted into the subconjunctival or under the fascia.

The complete dislocation of the crystal is more serious than the incomplete dislocation of the crystal. The crystal can be detached into the pupil region to cause pupil incarceration. The crystal axis is rotated by 90° after the trauma, the equator of the crystal is located in the pupil region or even the crystal is rotated by 180°, and the front surface of the crystal is opposite. Vitreous body.

After the crystal completely leaves the pupil area, the visual acuity is aphakic vision, the anterior chamber becomes deeper, the iris membrane, and the dislocated crystal can often move with the change of body position in the early stage. If the crystal breaks into the anterior chamber, it sinks deeper. Below the anterior chamber, the crystal diameter is smaller than in the normal position, but the convexity increases, the crystal is transparent and oily, the edge is golden and swelled, and the crystal opaque is a white disc, but the crystal passes through the pupil from the vitreous cavity. Some cases of pupillary blockage can occur during the process of detachment into the anterior chamber. If the pupil area is clear, good vision can be maintained, and the patient can be well tolerated. Sometimes the over-maturing cataract can be improved due to the crystal into the anterior chamber. Vision, crystals in the anterior chamber can be gradually absorbed, but more often, repeated crystal contact with the cornea causes severe iridocyclitis, corneal dystrophy and acute glaucoma. Crystals are broken into the vitreous cavity and are more common than detachment into the anterior chamber. The patient is well tolerated, but the final prognosis remains problematic.

The dislocation of the crystal varies from person to person. Many dislocation crystals can remain transparent for many years, but the dislocated crystals always develop in the denaturing direction; the epithelial cells gradually decompose, the cortical water ruptures, the cortical turbid liquefaction, the crystal capsule shrinks and Nuclear sinking forms a Mogan cataract (Morgagnian cataract), and partial and total absorption of crystals is less common.

Inspection of crystal dislocation

1. Physical examination: After dilation, the lens is examined with a slit lamp, paying particular attention to the position of the lens.

2. Auxiliary examination: Ultrasound examination of the eye must be performed.

Diagnostic identification of crystal dislocation

diagnosis

Dislocation of the lens caused by different causes: According to the body type, with or without history of trauma, dislocation of the lens, it can diagnose the dislocation of the lens caused by different causes.

Differential diagnosis

The identification of crystal dislocation is mainly the difference between the causes of the disease:

1. Traumatic crystal dislocation:

Eye trauma, especially ocular contusion, is the most common cause of dislocation of the lens. Traumatic dislocation of the lens is often accompanied by secondary cataract formation. The dislocated crystal can be detached into the anterior chamber or the vitreous cavity; if accompanied by an eyeball rupture, the crystal can be removed under the bulbar conjunctiva.

2, spontaneous crystal dislocation:

Spontaneous dislocation of the lens causes mechanical elongation of the suspensory ligament by intraocular lesions or due to inflammatory decomposition and degeneration. Crystal dislocation due to mechanical elongation of the suspensory ligament is common in bulls eye, staphyloma or eyeball expansion, and can also be seen in ciliary body inflammation adhesion or vitreous cord pulling crystal. The intraocular tumor can push and pull the crystal away from the normal position. Inflammatory destruction of the crystalline suspensory ligament can be seen in endophthalmitis or total ocular inflammation, and the suspensory ligament can be completely decomposed. Long-term chronic ciliary body inflammation can occur in the same pathological process, and the suspensory ligament can be occupied by the granule tissue of the ciliary body. Degeneration or malnutrition of the suspensory ligament is the most common cause of natural dislocation, often accompanied by degeneration and liquefaction of the vitreous, such as high myopia, old choroiditis or ciliary body inflammation, retinal detachment. Iron or copper rust can also gradually decompose the suspensory ligament. Another common cause is the over-mature period of senile cataract, and the degeneration of the lens also affects the lens suspensory ligament. Once the suspensory ligament is denatured, the crystal can spontaneously dislocate at any time due to its own weight or slight trauma or even force and cough.

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