Lens dislocation is a pathology characterized by a complete displacement of the lens into the vitreal cavity or anterior chamber of the eye. Clinical manifestations of the disease: sharp deterioration of vision, soreness and discomfort in the eye socket, phacodonaise and iridodonaise. For diagnosis, visometry, ultrasound of the eye, biomicroscopy, OCT, non-contact tonometry, gonioscopy are used. Treatment tactics are reduced to lensectomy, vitrectomy and implantation of an intraocular lens. In the postoperative period, the appointment of glucocorticosteroids and short-course antibacterial therapy is recommended.
H27.1 Lens dislocation
Lens dislocation (ectopia, dislocation) is a violation of the anatomical and topographic location of the biological lens, the cause of which is the failure of the ligamentous apparatus. According to statistics, the prevalence of congenital ectopia is 7-10 cases per 100,000 people. With hereditary predisposition, genetic mutations can be detected in 85% of patients. In 15% of patients, the disease occurs sporadically. Eye injury in 33% of cases is the cause of the acquired variant of pathology. Male and female individuals get sick with the same frequency. The disease is widespread everywhere.
Ectopia of the lens is a polyethological pathology. Degenerative-dystrophic changes in the fibers of the ciliary ligament, which are more often detected in elderly people, lead to the development of a spontaneous form. The main predisposing factor is chronic inflammation of the structures of the uveal tract or vitreous lesion. The main causes of dislocation:
- Genetic predisposition. Patients with Marfan, Ehlers-Danlos, Knist syndrome are most at risk of developing congenital ectopia. The disease often occurs with hereditary hyperlysinemia and sulfitoxidase deficiency.
- Traumatic injuries. This disease is one of the common complications of blunt trauma or penetrating injury of the eyeball, accompanied by damage to the ligamentous apparatus. In rare cases, dislocation occurs with contusion of the eyes.
- Cataract. Pathological changes in the capsule, capsular epithelium or the main substance that are observed in cataracts are significant risk factors for ectopia. The reason is a violation of the fit of the anterior and posterior zonular fibers.
- High degree of hypermetropia. Hyperopia is characterized by an increase in the longitudinal size of the eyeball. This leads to tension and the formation of micro-tears of the ligament, which contributes to ectopia.
- Aplasia of the ciliary girdle. This is a congenital malformation in which the ligamentous apparatus is completely absent. Agenesis of the ciliary girdle is revealed in the syndrome of amniotic constrictions.
In the mechanism of development of the congenital variant of the disease, the leading role is given to weakness, partial or complete absence of the ciliary ligament. The vast majority of patients with a genetic predisposition are characterized by a defect in the synthesis of collagen or elastin, a violation of protein metabolism. With a partial rupture of the ciliary girdle, the lens remains fixed to the parietal layers of the vitreous body, with a full one, it moves freely in the vitreal cavity. The dilation of the pupillary opening causes dislocation to the anterior chamber area, usually occurring in the “face down” position.
Violation of the attachment of the biological lens to the ciliary girdle in cataract entails dysfunction of the ligamentous apparatus. With hyperopia, overextension of the zinc ligament leads to its partial damage. An increase in ophthalmotonus or the performance of a minor load potentiates the rupture of the ciliary girdle and the occurrence of ectopia. When the eyeball is injured, the ciliary girdle is the most “weak” place, vulnerable to damage. This is due to the fact that the shock wave does not lead to the rupture of the capsule, but to deformation and stress of the fibers of the zinc ligament. Involutional changes in the lens masses and ligamentous apparatus provoke ectopia in elderly patients.
There are congenital and acquired, complete and incomplete forms of dislocation. Acquired ectopia is classified into traumatic and spontaneous. With incomplete dislocation, a ligament rupture occurs on 1/2-3/4 of the circumference. The lens is deflected towards the vitreal cavity. In the clinical classification , the following variants of complete dislocation are distinguished:
- Into the camera eyes. Dislocation causes damage to the cornea, iris and angle of the anterior chamber. There is a sharp rise in intraocular pressure (IOP) and a progressive decrease in vision. This condition requires urgent intervention.
- Into the vitreous body. In this variant of ectopia, the lens can be fixed or movable. Fixation is facilitated by the formation of adhesions to the retina or disc of the optic nerve (ZN). With a movable shape, the lens can move freely.
- Migrating. With a migrating dislocation, the lens of a small size has high mobility. It can move freely from the vitreous cavity to the chamber bounded by the iris and cornea, and back. The dislocation is indicated by the development of pain syndrome.
Symptoms of lens dislocation
Pathology is characterized by a severe course. In the congenital form of the disease, parents note a whitish-gray opacity of the anterior part of the eyeball in the child. There is a pronounced visual dysfunction, only the ability to perceive light is preserved. With a genetic predisposition, symptoms can develop at a more mature age. Patients associate the occurrence of clinical manifestations with minor physical exertion or mild injury. The accommodative ability is sharply disrupted. Attempts to fix the gaze lead to rapid fatigue, headache.
Patients with acquired form note that the moment of dislocation is accompanied by severe paroxysmal pain and a sharp decrease in visual acuity. The intensity of the pain syndrome increases over time. Patients complain of a feeling of “shaking” of the eye, redness of the conjunctiva, pronounced discomfort in the periorbital region. The development of phacodonaise in combination with iridodonaise provokes movements of the eyeballs. A limited area of separation of the iris from the ciliary body is revealed (iridodialysis). Patients note the irregularity of the pupil contour and the zone of “splitting” of the iris.
Most patients have signs of ophthalmohypertension. In 52-76% of cases, ectopia provokes the occurrence of secondary glaucoma. Patients are at high risk of joining inflammatory complications (iridocyclitis, retinitis, keratoconjunctivitis). The fixed form is accompanied by detachment and tears of the retina, degeneration of the cornea. Pronounced destructive changes or hernias of the vitreous body develop. The formation of adhesions with ZN predisposes to optic neuritis. The most severe complication of the disease is complete blindness, accompanied by pain syndrome.
Physical examination reveals a decrease in the transparency of the anterior segment of the eyes, which may be combined with signs of traumatic injury. When the eyes move, a facodon develops, which is detected by an ophthalmologist with focal illumination. When conducting a test with mydriatics, the reaction of the pupils is not observed. Special diagnostic methods include the use of:
- Contactless tonometry. When measuring intraocular pressure, it is possible to diagnose its increase. IOP reaches critical values only when the outflow of watery moisture is disturbed. Mobile dislocation causes a slight increase in ophthalmotonus.
- Visometry. Visual acuity decreases sharply regardless of the degree of transparency of the lens. With the additional use of computer refractometry, it is possible to diagnose the myopic type of clinical refraction.
- Ultrasound of the eyes. Ultrasound examination reveals dislocation in the anterior chamber area or vitreous body. A one- or two-sided rupture of the zinc ligament is determined. The vitreal cavity has an inhomogeneous structure. When the lens is fixed to the retina, its detachment occurs. The anterior-posterior axis is displaced. With a complete rupture, the capsule with the main substance acquires a spherical shape.
- Biomicroscopy of the eye. With the traumatic genesis of the disease, the injection of conjunctival vessels, hemorrhage foci is visualized. The transparency of optical media is reduced. Secondary corneal changes are represented by microerosive defects.
- Gonioscopy. When the displacement vector is directed anteriorly, the volume of the eye camera is sharply reduced. In patients with an incomplete form of pathology, the space limited by the iris and cornea is deep, without pathological changes. The angle of the front camera has an uneven structure.
- Optical coherence tomography (OCT). The study makes it possible to determine the nature of the location of the luxated lens, the type of damage to the zinc ligament. OCT is applied immediately before surgery to select the optimal surgical tactics.
- Ultrasound biomicroscopy. In the congenital variant of the disease, the technique allows detecting defects of the ciliary ligament for a period of 60 ° to 260 °. The lens is displaced in the horizontal and vertical planes. The depth of corneal damage is measured.
In the case of a traumatic origin of the disease, patients are additionally assigned X-ray orbits in direct and lateral projection. In the early postoperative period, measurement of IOP by the contactless method is shown. Electronic tonography is used to study the nature of HCV circulation 5-7 days after surgery. The study determines the risk of developing glaucoma.
Treatment of lens dislocation
When the biological lens is completely displaced, a lensectomy is indicated. In order to prevent traction on the eve of surgery, vitrectomy is performed. The main stage of the operation is lifting the lens from the fundus and removing it into the anterior chamber. For this purpose, the method of introducing perfluoroorganic compounds into the vitreous cavity is used. Due to the high specific gravity of perfluoroorganic compounds, they sink to the fundus and displace the pathologically altered substance outside. The next stage after lensectomy is implantation of an intraocular lens (IOL). Possible places of fixation of the IOL are the angle of the anterior chamber, ciliary body, iris, capsule.
At high core density, ultrasonic or laser phacoemulsification is used to remove the luxated lens. All remnants of vitreous, blood and fragments of the posterior capsule should be completely removed. Children’s patients are implanted with an artificial lens in combination with a capsule bag and a ring. In modern ophthalmology, techniques are used that allow the IOL to be fixed intrasclerally or intracorneally using suture techniques. At the end of the operation, subconjunctival administration of antibacterial agents and corticosteroids is indicated. If necessary, after the intervention, instillation of antihypertensive agents is prescribed.
Prognosis and prevention
Timely lensectomy in 2/3 of cases makes it possible to fully restore visual acuity and normalize the circulation of intraocular fluid. 30% of patients develop severe postoperative complications. Specific methods of prevention have not been developed. Non-specific preventive measures include the use of personal protective equipment when working in production conditions (glasses, masks). To reduce the likelihood of dislocation, patients with hypermetropic refraction are shown to correct visual dysfunction using glasses or contact lenses.