Angle closure glaucoma is a sharp increase in intraocular pressure due to blocking the outflow pathways of watery moisture. Pathology occurs against the background of age-related changes, non-inflammatory or traumatic ophthalmic diseases, some endocrine disorders. An attack of glaucoma is characterized by severe pain in the affected eye, loss of visual fields, the appearance of iridescent circles when looking at light. Diagnosis of the disease includes ophthalmoscopy, tonometry and functional tests. Treatment consists of an individual pharmacotherapy regimen, with the ineffectiveness of which microsurgical iridectomy is performed.
H40.2 Primary angle-closure glaucoma
The closed-angle form of glaucoma accounts for about 10% of all cases of increased intraocular fluid pressure. Pathology is more common among residents of the Asian region and is one of the main causes of vision loss. The maximum risk of the disease is observed among women aged 50-75 years. Angle-closure glaucoma is characterized by an acute onset and a rapidly progressive course, therefore it poses a serious problem for practical ophthalmology, requires emergency assistance to prevent irreversible pathologies of the visual apparatus.
Etiological factors of angle-closure glaucoma are diverse. Predisposition to the development of the disease is associated with the features of the anatomical structures of the eye, such as a small anterior chamber, a large lens, a thin root of the iris and the posterior position of the Schlemm canal. The immediate causes of the increase in intraocular pressure (IOP) are the following:
- Involutional changes. Age–related dystrophy of the eyeball structures is the basis of the etiology of primary angle-closure glaucoma. The initial signs of trabeculopathy and the functional block of the Schlemm canal can occur at the age of 35 years, significant disorders are diagnosed in the period of 50-55 years and older.
- Eye diseases. Secondary forms of glaucoma occur in patients with swelling cataracts, subluxation and dislocation of the lens. Less often, pathology is associated with wound, contusion or burn injuries, tumors of the ciliary body and choroid, mesodermal dystrophy of the iris.
- Systemic diseases. In rare cases, pathology is formed with somatic diseases affecting the structures of the ocular drainage system. Pathology is possible with Itsenko-Cushing syndrome, hypothyroidism, pathological menopause. An increase in IOP may be one of the signs of tetraethyl lead poisoning.
The elderly population and people with close relatives with glaucoma are at risk. An increased probability of the disease is observed in patients with high-grade myopia, patients who have suffered serious eye injuries. The provoking factors of the development of angle-closure glaucoma can be long-term use of glucocorticosteroids, work with a constant tilt of the head in office employees, seamstresses, beauty masters.
IOP is the pressure exerted by the elements of the eyeball and the intraocular fluid on the outer shell. Its value is mainly determined by the volume of watery moisture, since the mass of the lens and vitreous body is practically stable. In a healthy eye, the IOP level is 18-24 mm Hg. The amount of intraocular fluid in an adult ranges from 0.35-0.45 ml.
Watery moisture flows from the posterior chamber to the anterior chamber, after which it is drained through the angle of the anterior chamber (FCA) into the venous plexuses of the sclera. With angle-closure glaucoma, this outflow path is disrupted due to the overlap or sharp narrowing of the collector tubules, while the iris tightly adheres to the cornea at their junction. The condition is developing rapidly, IOP is rapidly increasing.
An increase in IOP in the closed-angle form of pathology causes mechanical deformation of the supporting structures of the optic nerve head, uneven deflection of the sclera optic plate and infringement of nerve fibers. The condition results from conduction disturbances in the optic nerves and leads to their atrophy. The pathology is aggravated by ischemic processes, which are caused by a decrease in blood perfusion pressure and vascular endothelial dysfunction.
According to etiopathogenesis, the disease is divided into a primary form that occurs in a previously healthy eye, and a secondary one that develops against the background of various ophthalmological pathologies. The first option is typical for middle-aged and elderly people, the second is found in all age groups. In ophthalmology, there are 4 stages of the formation of angle-closure glaucoma:
- I (initial). It is characterized by a periodic increase in IOP, against which there are small loss of paracentral fields of vision, expansion of physiological excavation of the optic nerve disk.
- II (developed). It is manifested by a constant decrease in visual fields by 10 ° or more, the formation of an arcuate scotoma of the Bjerrum. Intraocular pressure is constantly increased in the range of 25-32 mm Hg.
- III (far gone). It manifests by reducing the viewing angles by 15° or more or by dropping out large areas of the fields of view. Intraocular pressure exceeds 33 mm Hg.
- IV (terminal). It is established in case of complete blindness or inability to object vision while maintaining light perception.
An acute attack of the disease is manifested by severe pain in the eye and the corresponding half of the head, which resemble a migraine. A person complains of blurred vision, the appearance of black circles in front of his eyes, iridescent glare when looking at a light source. Severe pain is accompanied by nausea and vomiting, in severe cases, loss of consciousness is possible against the background of pain syndrome.
A subacute attack is manifested by a slight decrease in visual acuity, the appearance of blurred vision or colored circles in front of the eyes. Occasionally, patients notice a narrowing of the fields of vision: there is a need to turn their head to clearly see objects located on the side. Pain in the eyeball is weakly expressed or absent.
Glaucoma is the second cause of blindness worldwide after cataracts, up to 13% of cases result in complete loss of vision. In the absence of timely help with an acute attack, there is a sharp deterioration in the clarity of vision, atrophy of the optic nerve is rapidly progressing. Irreversible changes develop after a day from a sharp jump in IOP, which increases the risks of negative consequences.
The diagnosis of angle-closure glaucoma begins with the collection of complaints and anamnesis, an initial examination by an ophthalmologist. The examination reveals an injection of the vessels of the eyeball, persistent mydriasis in acute paroxysm and an indistinct dilation of the pupil in a subacute attack. The program of advanced diagnosis of the disease includes the following methods:
- Biomicroscopy. On examination, corneal edema, a shallow or slit-like anterior chamber, protrusion of the iris and swelling of its stroma are determined. With a prolonged attack, opalescence of the intraocular fluid of the anterior chamber is observed. With the help of gonioscopy, the FCA blockade is visualized.
- Tonometry. In acute paroxysm of angle-closure glaucoma, the level of intraocular pressure can reach 35 mmHg or more, in the subacute course, pressure indicators are within 30-35 mmHg. With control IOP measurements in the morning and evening, a difference of more than 5 mmHg is observed.
- Perimetry. The test for the breadth of the visual fields is included in the mandatory diagnostic program, allows you to assess the severity of damage to visual structures. The narrowing of the visible space along the periphery and the loss of visibility in the paracentral zones have diagnostic value.
- Functional tests. When conducting a pilocarpine test after 1 hour, the IOP decreases by more than 5 mmHg. To confirm the disease, a dark (load) test is also used: 60 minutes after being in the dark, intraocular pressure increases in patients with glaucoma.
The manifestations of angle-closure glaucoma must be distinguished from acute iridocyclitis, ophthalmohypertension (reactive uveal syndrome, pseudohypertension), glaucocyclitic crisis (Posner-Schlossman syndrome). Differential diagnosis is also carried out with injuries of the eyeball, pathologies that manifest themselves as “red eye” syndrome. An acute attack of glaucoma should be differentiated with migraine, hypertensive crisis.
To successfully stop the signs of the disease and prevent complications, treatment should be started early, preferably in the first 2 hours after the onset of acute symptoms. The basis of therapy is made up of eye drops in combination with oral remedies, if ineffective, parenteral drugs are used to reduce IOP. The therapeutic scheme is determined by the nature of the course of angle-closure glaucoma:
- An acute attack. Eye drops with M-cholinomimetics and beta-blockers are used, the action of which is aimed at narrowing the pupil and rapidly reducing pressure. In the first 4 hours, the drugs are instilled about 12 times. In case of insufficient efficacy, oral or parenteral diuretics are prescribed, in severe cases, a lytic mixture is administered in a hospital setting.
- Subacute attack. To normalize intraocular pressure, a 3-4-time application of M-cholinomimetics is sufficient, after which instillations of beta-blockers are prescribed for several days. Diuretics from the group of carbonic anhydrase inhibitors are used as systemic remedies for angle-closure glaucoma.
- Chronic form. The drugs of choice are locally acting myotics, which, according to indications, are enhanced with combined dosage forms. Neuroprotective therapy, vitamin and mineral complexes are recommended for the prevention of visual impairment.
In acute and subacute seizures, laser iridectomy is prescribed – a radical way to normalize IOP. The operation is aimed at eliminating the pupillary block and creating additional ways of fluid outflow from the rear chamber. As a result, the intraocular pressure is leveled, the drainage system of the eye is resumed. In the chronic form of glaucoma, iridectomy is performed after unsuccessful conservative treatment.
Prognosis and prevention
The outcome of the disease depends on the time of diagnosis and the amount of therapy. With rapid relief of the attack, it is possible to preserve visual function, but delay in treatment is fraught with persistent vision loss or even blindness. Patients with angle-closure glaucoma are registered with an ophthalmologist at a dispensary, visit a doctor at least 2-3 times a year. Prevention consists in controlling the dynamics of the pathological process and the rational use of pharmacotherapy.
To prevent the disease and its complications, patients are recommended to adjust their lifestyle. It is necessary to minimize nervous shocks in the family and at work, to devote enough time to sleep, quiet rest. With glaucoma, light physical labor is useful, while head tilts down should be avoided. To prevent an increase in IOP, it is worth giving up strong coffee and tea, hot baths and saunas, prolonged visual loads.