lens heterotopia
Introduction
Introduction to lens ectopic Under normal conditions, the lens is suspended by the lens suspensory ligament on the ciliary body, and its center is almost identical to the visual axis. The partial or total loss or disconnection of the lens suspensory ligament due to congenital, traumatic or pathological causes causes the suspension force imbalance or loss of the lens, which may cause the lens to leave the normal physiological position, called ectopialentis. basic knowledge The proportion of illness: 0.005% Susceptible people: no special people Mode of infection: non-infectious Complications: ametropia cataract glaucoma vitreous lens dissolving glaucoma retinal detachment retinopathy retinopathy edema corneal disease
Cause
Ocular ectopic cause
(1) Causes of the disease
Due to the abnormal development of the partial lens suspensory ligament, the traction of the lens is unbalanced, and the lens is displaced in the opposite direction to the poorly developed suspensory ligament. It is called congenital lens ectopic, which can be used as an isolated ocular abnormality. Occurring alone, can also be associated with other ocular dysplasia or systemic dysplasia (mesenchyelia, especially systemic syndrome of bone dysplasia), ocular trauma, especially eyeball contusion is the most common cause of lens ectopic, spontaneous Lens ectopic is caused by weakening of the lens suspensory ligament or mechanical elongation of the suspensory ligament due to intraocular lesions for some reason such as inflammation and degeneration.
(two) pathogenesis
Simple lens ectopic
There are obvious genetic predispositions, mostly autosomal dominant inheritance, a few are autosomal recessive inheritance, often bilateral symmetry, may be associated with fissure-like pupillary malformation, the cause of dysplasia of the suspensory ligament is still unknown, although in the uterus Inflammation, ciliary body atrophy of neuroectoderm, etc. are possible predisposing factors, but the exact mechanism remains unclear. If accompanied by ovarian dysplasia and other abnormalities in mesoderm, it may be related to mesoderm developmental disorders.
2. Lens ectopic with other ocular dysplasia
Commonly there are microspherophakia, coloboma of the lens, iris coloboma, anuridia and ectopia pupillae.
3. Lens ectopic with systemic dysplasia
(1) Marfan syndrome: an autosomal dominant genetic disorder characterized by extensive disorders of the mesoderm throughout the body, characterized by abnormalities in the eye, cardiovascular and skeletal systems, which was first reported by Marfan in 1896. The abnormality of the eye is characterized by ectopic lens, especially the upward and the lateral displacement. Because the iris pigmentation layer is absent, the posterior transillumination test is positive, and the partial absence of the pupillary large muscle makes it difficult for the drug to dilate the pupil. Department can also have iris corneal angle abnormalities, choroid and macular defects, can also produce glaucoma, retinal detachment, nystagmus, strabismus, amblyopia and other complications, skeletal abnormalities are characterized by long bones of the hands and feet, long head and long face, cardiovascular The abnormal manifestations are that the cardiac foramen ovale is not closed, the aneurysm and the aortic stenosis are more common than men.
(2) Marchesani syndrome: an autosomal recessive genetic disease, the patient is short, the limbs (toe) are short and thick, the cardiovascular system is normal, the lens is spherical, less than normal, often ectopic below the nose, prone to glaucoma, Often accompanied by refractive high myopia, other eye abnormalities include ptosis, nystagmus, small cornea and so on.
(3) homocystinuria (homocystinuria): is an autosomal recessive disorder, most commonly affecting bone, it is characterized by osteoporosis and systemic thrombosis, the lens is ectopic under the nose, easy to dislocate In the anterior chamber and vitreous cavity, the tissue structure and ultrastructure of the lens suspensory ligament are abnormally changed. The eye can also be combined with congenital cataract, retinal detachment and degeneration, and no iris. The disease is caused by the lack of desulfurized ether in patients. Synthetase does not convert homocysteine to cystine. The following is a comparison of the above three syndromes.
4. Traumatic lens ectopic
It is most common in eyeball contusions. Trauma can directly lead to incomplete or complete rupture of the lens suspensory ligament, resulting in incomplete dislocation or total dislocation of the lens.
5. Spontaneous lens ectopic
It is caused by inflammation and degeneration that the suspensory ligament becomes weak or due to mechanical elongation of the suspensory ligament due to intraocular lesions. The lens ectopic caused by mechanical elongation of the suspensory ligament is common in bull's eye, grape swelling or eyeball expansion. Seen in the ciliary body inflammation adhesion or vitreous cord pulls the lens, the intraocular tumor can push and pull the lens away from the normal position, the inflammation destroys the lens suspensory ligament can be seen in endophthalmitis or total ocular inflammation, the suspensory ligament can be completely decomposed, long-term chronic ciliary body Inflammation can occur in the same pathological process, the suspensory ligament can be occupied by the granule tissue of the ciliary body, degeneration of the suspensory ligament or malnutrition is the most common cause of spontaneous dislocation, often accompanied by degeneration and liquefaction of the vitreous, such as high myopia, stale Crohnette or ciliary body inflammation, retinal detachment, etc., iron or copper rust can also gradually degenerate the suspensory ligament, another common cause is the over-mature period of senile cataract, lens degeneration changes also involve lens suspension Ligament, once the suspensory ligament is denatured, the lens may even force and cough due to its own weight or slight trauma Spontaneous ectopic can occur at any time.
Prevention
Lens ectopic prevention
Prevent eyeball trauma and actively treat primary eye diseases.
Complication
Pleural ectopic complications Complications ametropia cataract glaucoma vitreous lens dissolution glaucoma retinal detachment retinopathy retinopathy edema keratopathy
Refractive error
It is often more serious.
2. Uveitis
It is a common complication of lens ectopic. There are two kinds of uveitis caused by ectopic lens. One is that the uveal tissue is caused by the mechanical stimulation of the lens; the other is that the ectopic lens becomes overripe. Cataract, which produces lens allergic uveitis, both uveitis are intractable inflammation and can cause secondary glaucoma.
3. Secondary glaucoma
It is also one of the most common complications. The lens is in the pupil area or the vitreous is incarcerated in the pupil, which can produce pupillary glaucoma. The long-term lens dislocation can produce lens-soluble glaucoma, and the lens ectopic caused by eyeball contusion. The iris root can be retracted, and the cleft palate produces secondary glaucoma.
Retinal detachment
It is a common and serious complication of lens ectopic, especially in eyes with congenital anomalies, such as Marfan syndrome, and even binocular, the treatment of retinal detachment caused by lens dislocation is difficult, because dislocated lens often hinders the observation of retinal tears. The exact location and extent of retinal detachment, if the lens is removed first, the vitreous body will be lost, the retinopathy will be aggravated, and the time of retinal detachment surgery will be delayed.
5. Corneal opacity
In recent years, it has been noted that lens dislocation can cause corneal opacity. The lens is dislocated into the anterior chamber and contacts the corneal endothelium, resulting in corneal endothelial cell injury or decompensation, which can cause corneal edema or bullous keratopathy.
Symptom
Lens ectopic symptoms common symptoms lens displacement corneal ulcer aphakic eye double vision lens iron deposition
1. Incomplete lens dislocation
The lens suspensory ligament partially relaxes or breaks, causing the lens to deviate from the normal physiological position, but the displaced lens is still in the pupil area. The vitreous cavity in the posterior plane of the iris is called incomplete dislocation of the lens. The symptoms caused by incomplete dislocation of the lens depend on the lens. The degree of displacement, if the axis of the lens is still on the visual axis, only the lensy myopia caused by the relaxation of the suspensory ligament and the increase of the curvature of the lens may occur. If the lens axis is horizontal, vertical or oblique, it may cause Frequent astigmatism difficult to correct by glasses or contact lenses. The more common incomplete dislocation is longitudinal displacement of the lens. Single eye double vision can be seen. The anterior chamber is deepened by eye slit lamp examination, iris tremor, the lens is gray, and even the equator can be seen. The ruptured suspensory ligament, the vitreous iliac crest can enter the anterior chamber, the surface is pigmented, and the crescent-shaped fundus reflex and the bifocal basal image can be seen under the ophthalmoscope.
2. Complete dislocation of the lens
The lens suspensory ligament is completely disconnected, so that the lens completely leaves the normal physiological position, and the displacement of the anterior chamber or the vitreous cavity is called full dislocation of the lens. There are several cases:
(1) The lens is incarcerated in the pupil.
(2) The lens is detached into the anterior chamber.
(3) The lens is detached into the vitreous cavity, floats on the vitreous body or sinks into the vitreous.
(4) The lens enters the space under the retina and the space under the sclera through the retinal tear.
(5) The lens is perforated through the corneal ulcer, and the scleral rupture hole enters the subconjunctival or under the fascia of the eyeball.
The complete dislocation of the lens is more serious than the incomplete dislocation. The lens can be incarcerated in the pupil area and cause pupillary block. The lens axis rotates 90° after trauma, the equatorial part of the lens is located in the pupil area and even the lens is 180° transposition. The anterior surface of the lens Opposite the glass body.
After the lens completely leaves the pupil area, the visual acuity is equivalent to the aphakic vision, the anterior chamber becomes deeper, and the iris tremors. The dislocated lens can move with the change of body position in the early stage. If the lens breaks into the anterior chamber, it sinks before the deepening. Below the room, the lens diameter is smaller than in the normal position, the convexity increases, the transparent lens is oily, the edge is golden luster, the opaque lens is a white disc, and the lens is inserted from the vitreous cavity through the pupil before it enters. Some cases may cause pupillary block in the process of the room, causing acute glaucoma. If the pupil area is clear, good vision can be maintained, the patient can be well tolerated, and sometimes the over-maturing cataract can improve vision due to the lens going into the anterior chamber. The lens in the room can be gradually absorbed, but it is more common that the lens repeatedly contacts the cornea and the iris ciliary body to cause severe iridocyclitis, corneal dystrophy and acute glaucoma. The lens is detached into the vitreous cavity and is more common than the anterior chamber. And the patient is well tolerated, but the final prognosis remains problematic.
Examine
Examination of lens ectopic
Genetic examination
It can be performed when it is suspected to be a congenital lens ectopic to confirm the diagnosis.
2. Blood, urine test
Identify whether homocysteine (homocystinuria) is included to rule out homocystinuria.
3.B-ultrasound
When the lens is completely dislocated and the position cannot be clearly determined, the eyeball B can be used for searching.
4. Heart color Doppler examination
Clear heart valve disease and hemodynamics.
Diagnosis
Lens ectopic diagnosis
According to clinical manifestations and eye signs, it is not difficult to confirm the diagnosis.
