Ectopia lentis is a displacement of the lens relative to its physiological position, which develops as a congenital condition or is the result of injuries, ophthalmic diseases. Pathology is manifested by deterioration of visual acuity, double vision, pain in the area of the affected eye. Headache, conjunctival hemorrhages, inflammation of deep structures of the eye are possible. Diagnosis requires biomicroscopy, gonioscopy, visometry and other special ophthalmological studies. Treatment of ectopia is surgical: removal of the dislocated lens with subsequent prosthetics.
H27.1 Dislocation of the lens
Ectopia lentis is a rare disease that occurs with a frequency of about 7-10 cases per 100 thousand population. The disease has no gender differences, can develop in patients of any age, is more often diagnosed in children and young people. Ectopia is important for practical ophthalmology, because without treatment, the disease causes an irreversible decrease in vision in the affected eye, worsens the quality of life, and in some cases ends in disability.
Ectopia lentis, which is detected in childhood, most often occurs under the influence of diseases of connective tissue and metabolism. Pathology in adults develops with lesions of the ligamentous system of the lens, due to eye injuries. All the reasons that provoke an anomaly of the structures of the eyeballs can be divided into the following categories:
- Hereditary pathologies. Ectopia lentis is one of the typical signs of Marfan syndrome. In addition, it can occur in people suffering from Vail-Markezani syndrome, Marshall syndrome, Stickler syndrome, homocystinuria.
- Eye injuries. With direct mechanical damage to the zinc ligament, the fixation of the lens in the anatomically correct position is disrupted. The severity of the condition is determined by the degree of damage to the ligaments and the safety of other structures.
- Age-related degeneration. Elderly patients develop physiological hyperopia, the structure of the ligaments of the eyeball is disturbed, which contributes to the displacement of the lens.
- Ophthalmic diseases. The risk of ectopia increases in the presence of chronic infectious and inflammatory diseases of the eye. Anomalies occasionally occur as a complication of overripe cataracts, high degree of myopia, aniridia.
Normally, the lens is a biconvex lens, which is an important part of the refractive and light-conducting system of the eye. The organ has a layered structure, surrounded on all sides by intraocular fluid, from which it receives nutrients. It is fixed to the eyeball with the help of the ciliary girdle — a circular supporting ligament of the ciliary body. It departs from the epithelium of the ciliary processes and weaves into the capsule of the biolens.
Ectopia occurs with various types of damage to the zinc ligament. With the congenital nature of the disease, the pathological process begins in the period of intrauterine development: irregular connective tissue fibers are formed, which cannot hold the organ in a normal position. The acquired forms of lesion are based on a mechanical or degenerative lesion of the ligamentous apparatus.
Subluxation of the lens:
- 1 degree — partial damage to the zinc ligament along the entire circumference, the lens is in a physiological position.
- Grade 2 — ligament rupture on one side, as a result of which the lens shifts to the healthy side.
- Grade 3 — damage to more than half of the circumference of the ciliary ligament, which is accompanied by pronounced ectopia in the anteroposterior direction.
Dislocation of the lens:
- Into the front camera of the eye.
- Into the vitreous body: a fixed, mobile or migrating lens.
M. Weiswohl and N. Kasahara (2009) distinguish 4 classes of ectopia. The first class is prognostically favorable, corresponds to the initial degree of subluxation. In the second class, the lens fills the pupil by 2/3, in the third — by 1/3, and in the fourth — it is completely absent from the pupil. Based on this classification, in 2013 A. Chandra and co-authors proposed an expanded version that takes into account the direction and nature of the displacement of the optical center of the lens.
Symptom of ectopia lentis
With a congenital form of pathology, parents and a neonatologist, when examining a child, notice a clouding of the eye, which at the same time may acquire a dirty white hue. In the future, such a patient has reduced visual acuity or complete blindness of the damaged eye. The clinical picture is complemented by symptoms of the underlying disease: asthenic physique and hypermobility of joints in Marfan syndrome, facial deformities and arthropathy in Stickler syndrome, etc.
Acquired dislocations of the lens are characterized by more obvious and diverse symptoms. With traumatic ectopia, there is a dull pain in the damaged eyeball, which is combined with blurred vision, hemorrhages in the conjunctival membrane, and hematomas around the orbit are also possible. Headaches are often bothered, more pronounced on the side of the lesion. With ectopia on the background of eye diseases, the features of symptoms are determined by the underlying pathology.
A characteristic manifestation of any form of ectopia is considered to be a sudden deterioration of vision in combination with double objects (diplopia). For a dislocated lens, it is typical to maintain diplopia even when one eye is closed. In addition, patients note discomfort and a feeling of a foreign body in the eye, redness of the conjunctiva, and when looking closely at the eyes in the mirror, you can see a trembling iris.
Ectopia is accompanied by progressive loss of vision, which eventually leads to blindness. If the ligamentous apparatus is completely destroyed, the lens can move freely in the vitreous body, which is fraught with inflammatory processes (vitrites), secondary glaucoma, hemorrhages and retinal detachment. The risk of complications is directly proportional to the time before the start of ectopia treatment, which determines the importance of early diagnosis and selection of optimal correction tactics.
During the physical examination of the patient, there is a tremor of the iris, clouding of the pupil, a decrease in the depth of the anterior eye chamber is possible. During the general examination, it is necessary to pay attention to the condition of the skin and joints, the structure of the skeleton, which helps to suspect congenital connective tissue diseases. To assess the degree of ectopia, to find out its root cause, the following diagnostic methods are carried out:
- Extended ophthalmological examination. To assess visual acuity, visometry is performed, the volume of the visual fields is measured using perimetry. Gonioscopy is necessarily performed to study the anterior chamber of the eye and biomicroscopy, which gives valuable information about the state of the ocular anatomical structures.
- Additional instrumental methods. Ultrasound examination of the eye is a fast and non—invasive method of assessing disorders, which is prescribed at any age. To clarify the anatomical features, optical coherence tomography is used, in case of eye injuries, an X-ray of the skull is shown.
- Consultation of a geneticist. If an ophthalmologist suspects the congenital nature of ectopia and its connection with hereditary connective tissue syndromes, medical and genetic counseling of the patient and next of kin is necessary. If necessary, specialized biochemical or genetic analyses are recommended.
Treatment of ectopia lentis
Conservative methods have no significant effect in ectopia and are used only for the treatment of concomitant eye diseases, if necessary. The basis of treatment is an ophthalmosurgical method — removal of the displaced biolens, restoration of the normal anatomy of the eyeball, prosthetics. In modern ophthalmology, several methods of correction of ectopia are used:
- complete extraction of the lens together with the capsule bag and subsequent extracapsular fixation of the artificial lens-prosthesis;
- a more gentle phacoaspiration with the preservation of the capsule bag in which the lens is installed;
- transciliary removal with simultaneous vitrectomy.
At the initial stages of lens subluxation and in the postoperative period after the replacement of the organ with an artificial lens, patients require optical correction. To achieve clear binocular vision, an individual prescription for glasses is issued. Also, patients are regularly under the supervision of a doctor to monitor the safety of visual function, the position of the natural or artificial lens.
Prognosis and prevention
With early ophthalmic surgery and rational selection of the method of optical correction in ectopia, it is possible to completely preserve vision. Prognostically unfavorable is a complete dislocation, which is accompanied by mechanical or inflammatory lesions of the constituent elements of the eyeball. Prevention of ectopia is to prevent injuries and eye diseases.