Primary angle-closure glaucoma: causes, symptoms, diagnosis, treatment

Closed-angle glaucoma, developing with predisposing forms of the iris, is called primary closed-angle. Pathology can be with acute, subacute and secondary chronic closure of the angle with a pupil block or a flat iris. With all forms of angle closure, the basis is the mechanical blockade by the peripheral part of the iris of the outflow of aqueous humor through the trabecular network. When the primary acute, subacute and chronic closure of the angle is relatively high pressure behind the iris, it pushes it forward. When the shape is flat, the iris is pushed anteriorly by rotated ciliary processes.

The term "primary" is confusing, since it implies an unknown mechanism, although in fact the mechanism of the development of the disease is clear. However, this definition continues to be used, it distinguishes primary glaucoma from secondary closed-angle, for example, from neovascular, neoplastic and other forms of glaucoma.

[1], [2], [3], [4], [5], [6], [7], [8], [9]

Epidemiology of primary closed angle glaucoma

Among white patients, the prevalence of a narrow angle reaches 2%, and the level of development of an acute angle-closure glaucoma is 0.1% (OZUG). The Eskimo's frequency of development of this disease is 40 times higher. Acute closed-angle glaucoma among the black population is less common, they develop chronic closed-angle glaucoma more often. In persons of the Asian race, the incidence rate of acute closed-angle glaucoma is higher than that of the white race, but lower than that of the Eskimos. The ratio of acute closed-angle glaucoma in women in relation to men is three to four. The highest prevalence of the disease by age is 55-65 years. Risk factors are hypermetropia and a small anterior chamber.

[10], [11], [12], [13], [14], [15], [16], [17]

Pathophysiology of primary closed-angle glaucoma

Pressing the iris sphincter toward the anterior capsule of the lens causes an increase in pressure behind the iris, leading to predisposing persons to bend forward and close the trabecular network. As a result, the intraocular pressure rises. The contact of the pupil with the lens and the increase in pressure beyond the iris are called the relative pupillary block. If the relative pupillary block is quite extensive, and the angle is very narrow, the trabecular network is completely closed, intraocular pressure sharply rises and acute acute angle glaucoma develops. If the relative pupillary block is weakly expressed, the angle is narrow, but not closed, and the trabecular network is blocked only a short distance, in this case the intraocular pressure rises very slowly, often for many years. Such a process is called a chronic primary closure of the angle. Subacute angle-closure glaucoma is located between acute and chronic, depending on the time during which the intraocular pressure rises.

Symptoms of primary closed angle glaucoma

Sharp angle closure

Symptoms develop from a slight unilateral blurred vision and pain to acute pain, nausea, vomiting and sweating. Such symptoms usually worsen in the evening. Attacks can be triggered by fatigue, poor lighting, stress and prolonged work at close range from the eyes.

Closer closing angle

Symptoms of subacute angle closure: intermittent pain attacks, blurred vision. Symptoms develop in low light, stress, fatigue and work at close range from the eyes. Sleep can interrupt the beginning of an attack. This condition can be taken as a headache with migraines.

Chronical closing angle

Characteristic of the absence of symptoms. When the angle is completely closed, the pressure rises sharply, the patient can complain of pain.

Diagnosis of primary closed angle glaucoma

Biomicroscopy and gonioscopy

Sharp angle closure

When examining the affected eye, a slightly enlarged pupil is defined, a pronounced mshjunctival injection, corneal edema and a small anterior chamber. Iris is often in the position of a classic bombing. Intraocular pressure can reach 80 mmHg. Often visible are an easy and accurate suspension and opalescence. Conduction of gonioscopy is more difficult due to corneal edema. If possible, the iris is visible, covering the trabecular network.

It is necessary to carefully examine the second eye, since almost always it also has a small front camera with a narrow angle.

Closer closing angle

The affected eye can be calm or with a slight injection of conjunctiva, cell suspension and opalescence, if the attack was recently. The front camera can be a little shallow, a light form of bombardment of the iris is possible. With gonioscopy, a narrow but not closed angle is defined.

Chronical closing angle

The eye is usually calm, the angle is a little narrow. With gonioscopy, a narrow angle is visible with wide zones of peripheral anterior synechiae. In more light cases, the trabecular network is viewed in small sections of the corner.

Rear Pole

Sharp angle closure

At the beginning of increased intraocular pressure, the optic nerve disk is swollen, hyperemic. A prolonged attack leads to the appearance of pallor of the disc with disproportionate to the excavation of the optic nerve disk (DZH) by defects in the visual fields.

With intraocular pressure higher than diastolic pressure, an arterial pulsation is detected in the optic nerve disc. If intraocular pressure exceeds the values of perfusion pressure of the central artery of the retina, retinal ischemia develops.

Closer closing angle

With frequent repetitions over a long period of time, the excitation of the optic nerve disc expands.

Chronical closing angle

On the optic nerve disk, typical changes associated with a prolonged increase in intraocular pressure are observed.

[18], [19], [20], [21], [22], [23], [24]

Treatment of primary closed angle glaucoma

Sharp angle closure

To interrupt attacks of acute closed-angle glaucoma, the relative pupillary block must be eliminated. Compulsory treatment is peripheral iridectomy, which prevents further attacks of rising pressure.

When compression (gonioscopy with compression) on the central area of the cornea with the Zeiss lens, occasionally the angle opens, leading to a transient increase in pressure in the anterior chamber and a mechanical opening angle.

Interrupt the attack can be pharmacologically, affecting the sphincter or dilator of the iris. Thus the sphincter of the iris moves away from the surface of the lens to the critical zone of 4-5 mm, but this method is not always successful, it can worsen the situation with further strengthening of the relative pupillary block. In addition, the attack is interrupted by drugs that suppress the production of watery moisture and osmotic means, while reducing intraocular pressure and dehydration of the vitreous, allowing the iridochromostalikovoy diaphragm to move backward. As a result, the hydrodynamics that led to the development of the relative pupillary block changes.

The most common method of treatment is the initial reduction in pressure by osmotic drugs and agents that reduce the production of intraocular fluid. After disappearance of edema of the cornea, peripheral laser iridotomy is performed.

Closer closing angle

The main method of treatment is laser peripheral iridotomy.

Chronical closing angle 

Treatment includes laser peripheral iridotomy to prevent further closure of the angle. In the trabecular network, damage can already occur, and despite functioning iridotomy, intraocular pressure remains high, which makes it necessary to continue taking medications that reduce intraocular pressure.