Glaucoma: an overview of information

Glaucoma is a chronic eye disease, among which the main symptoms are increased intraocular pressure, as well as worsening of visual functions (fields and visual acuity, adaptation, etc.) and development of marginal excavation of the nipple of the optic nerve.

Glaucoma is a very frequent and dangerous eye disease. Glaucoma accounts for 4% of all eye diseases. Now glaucoma is the main cause of incurable blindness and very deep disability. 25% of all blinded from various eye diseases are patients who have lost their eyesight from glaucoma.

The main cause of irreversible blindness in the world is the different forms of glaucoma. All types of glaucoma can be divided into primary glands (defeat of two eyes, no data on previous damage) and secondary (eye damage due to infectious process, mechanical effect or neovascularization, often only one eye is affected, sometimes bilateral damage).

Primary glaucoma is divided into separate forms depending on the width of the angle of the anterior chamber of the eye. With angle-closure glaucoma, intraocular pressure increases as a result of disturbed outflow of intraocular fluid in the formation of synechia between the iris and the trabecular network, and with open-angle glaucoma, the intraocular fluid enters the trabecular network unimpeded. There are also different types of primary glaucoma, depending on the age of manifestation of the disease. Glaucoma, which develops soon after birth, is called congenital; juvenile glaucoma develops from childhood to 40 years; glaucoma, which manifests after 40 years, is called open-angle glaucoma of adults.

The main symptoms of glaucoma described A, Gref (1857):

1. increased intraocular pressure;
2. decreased visual function;
3. change of the fundus.

Glaucoma occurs at any age (even in newborns), but a significant spread of glaucoma is observed in the elderly and senile.

Definition of glaucoma

Since the moment when the term was first used in ancient Greece, the definition of glaucoma has changed dramatically; now for different people it has a different meaning. The classification is being improved so far, which sometimes leads to confusion during the discussion. Until the second half of the XIX century, the diagnosis of glaucoma was based on the presence of symptoms: blindness or, later, pain. The development of statistics, the availability of a tonometer and the development of the concept of the disease as a deviation from the norm led to the definition of glaucoma from the position of increasing intraocular pressure more than 21 mm Hg. (exceeding the double standard deviation from the mean value) or more than 24 mm Hg. (exceeding the triple standard deviation from the mean value).

Numerous studies conducted in the 1960s showed that only 5% of people with intraocular pressure are above 21 mm Hg. There is damage to the optic nerve and narrowing of the visual fields, while in 1/2, patients with glaucoma-specific changes in the optic nerve and visual fields, the level of intraocular pressure is within normal limits. This led to a global rethinking of the definition of glaucoma. Many authors began to use the terms "low-pressure glaucoma", "normal pressure glaucoma" and "high-pressure glaucoma". More and more attention is paid to the optic nerve, and many researchers do not take into account the characteristic changes caused by angle-closure glaucoma (pain and concomitant changes in the cornea, iris and lens), focusing only on the optic nerve. This led to the definition of glaucoma as a characteristic optical neuropathy. Later, some authors divided glaucoma into an IGD-dependent and IGD-independent. Glaucoma is defined as a process leading to characteristic changes in the tissues of the eye, partly caused by intraocular pressure outside the connection with the level of intraocular pressure. Since almost all signs and symptoms of glaucoma early and advanced stage observed in people who are not suffering from glaucoma, it is very important to identify signs that are characteristic only (or almost only) for glaucoma.

[1], [2], [3], [4], [5], [6],

Epidemiology of glaucoma

Glaucoma is defined in people of any age and on any territory. Estimates of the prevalence of glaucoma vary significantly, which is due to differences in the definition of glaucoma, examination methods and the severity of the population of a family of weakly related conditions, called primary open-angle glaucoma. Congenital glaucoma is an extremely rare individual nosology. Most types of juvenile glaucoma are genetically determined and, although more common are congenital types of open-angle glaucoma, are considered relatively rare forms of the disease. Most patients with glaucoma are over 60 years old. The prevalence of glaucoma in African Americans over 80 years may exceed 20%.

Summarize data on the prevalence of blindness due to glaucoma due to the fact that glaucoma is a group of diseases and has a different definition is difficult. Nevertheless, the prevalence of blindness as a result of glaucoma is clearly increasing with age, especially in the African American population.

It is estimated that in different countries glaucoma occurs annually in 2.5 million people. In 3 million people, blindness is due to open-angle glaucoma. In the US, about 100,000 people are blind to both eyes because of glaucoma.

[7], [8], [9], [10], [11], [12],

Risk factors for the development of glaucoma

1. Organization of genetic material
Presence in a family history of cases of vision loss as a result of glaucoma Identification of the glaucoma gene
2. Data on intraocular pressure
MmHg.	The probability, in the final analysis, of the development of glaucoma
> 21	5%
> 24	10%
> 27	50%
> 39	90%
3. Age
Years	Level of distribution of glaucoma
<40	Rarely
40-60	1%
60-80	2%
> 80	4%
4. Vascular factors
Migraine Vasospastic disease Raynaud's disease Hypotension Hypertension
5. Myopia
6. Obesity

Risk factors for blindness due to glaucoma

1. The course of the disease can cause blindness *
2. Low availability of care:
   • geographical;
   • economic;
   • inaccessibility of care
3. Low self-service ability
   • intellectual limitations;
   • emotional limitations;
   • socioeconomic troubles

* The severity of primary open-angle glaucoma can vary greatly: in some patients, even in the absence of treatment, the disease does not progress, while in others. Despite the treatment, fast blindness occurs.

Glaucoma - Causes

Pathophysiology of glaucoma

A distinctive feature of glaucoma is damage to the tissues of the eye, especially the optic nerve. As a result of exposure to toxic substances and autoimmune mechanisms, damage and, ultimately, loss of ganglionic cells of the retina occur, leading to tissue atrophy and structural damage, which can enhance the damaging effect of IOP.

The final stage of the pathogenesis of all types of primary open-angle glaucoma is the death of retinal ganglion cells due to apoptosis or sometimes necrosis. This can lead to further damage to the retina, optic nerve and brain. Existing feedbacks supplement the simplified scheme.

Pathogenesis of eye tissue damage in glaucoma

A. Intraocular pressure (any level) → Mechanical deformation of the tissue (cornea, lattice plate, neuron, blood vessels) → Cell damage - vascular damage → Cell death in necrosis, more often apoptosis → Atrophy of tissues (thinning of the layer of nerve fibers, ) →

B. Increased cytotoxicity, growth factor deficiency, autoimmune mechanisms → Cell damage → Cell death (especially, retinal ganglion cells) → Atrophy of tissues → Structural changes

Some factors involved in tissue damage in glaucoma

• Mechanical damage
  • Stretching of the grating plate, blood vessels, corneal back epithelium cells, etc.
• Abnormal structure of glial, nervous or connective tissues
• Lack of metabolites
  • Direct compression of neurons, connective tissue and vascular network of intraocular pressure.
  • Lack of neurotrophils:
    • secondary, as a result of mechanical blockade of axons;
    • genetically determined;
    • deficiency of nerve growth factors
  • Ischemia and hypoxia:
    • disturbance of autoregulation of retinal vessels and choroida;
    • decreased perfusion:
      • acute / chronic,
      • primary / secondary;
    • violation of oxygen transport
• Autoimmune mechanisms
• Violation of protective mechanisms
  • Deficiency or inhibition of NO-synthase
  • Abnormal Heat Shock Protein
• Toxic agents for retinal ganglion cells and other tissues
  • Glugamate
• Genetic predisposition
  • Abnormal structure of the optic nerve:
    • Large holes in the trellis plate;
    • a large scleral canal;
    • anomaly of connective tissue;
    • vascular abnormality
  • Anomaly of the trabecular network:
    • decreased permeability of the intercellular matrix;
    • anomaly of endothelial cells;
    • anomalous molecular biology

Symptoms of glaucoma

An acute attack of glaucoma can develop at any stage of the disease. An acute attack of glaucoma can be played out without any seemingly obvious reasons. In other cases, an acute attack of glaucoma is promoted by a strong emotional shock, an infectious disease, inaccuracies in eating or drinking, erroneous instillation into the eye of atropine or other means dilating the pupil. Therefore, in the treatment of elderly patients prone to increased intraocular pressure, I must refrain from the appointment of these funds.

An acute attack of glaucoma on a healthy eye often occurs without any reason.

An acute attack of glaucoma begins suddenly, most often at night or in the morning. There is a sharp pain in the eye, orbit. Headache is accompanied by vomiting, general weakness of the body. Patients are deprived of sleep and appetite. Such common symptoms of an acute attack of glaucoma can cause diagnostic errors.

Acute attack of glaucoma is accompanied by pronounced phenomena from the side of the eye: edema of the eyelids and conjunctiva, often there is tearing.

Glaucoma - Symptoms and signs

Diagnosis of glaucoma

The focus of the clinical examination of a patient with suspected primary open-angle glaucoma is different from the emphasis of a standard examination. The most important stage is the careful detection of the afferent pupillary defect (AZD). Afferent pupillary defect can be detected before the appearance of changes in the visual fields. In addition, the afferent pupillary defect indicates damage to the optic nerve, which allows us to begin to search for the causes of this damage. The search for an afferent pupillary defect is an integral part of the examination of a patient suffering from glaucoma.

[13], [14], [15], [16], [17], [18]

Examination and biomicroscopy

A biomicroscopic study of a patient suffering from glaucoma differs from a standard examination in that the physician draws attention to the local side effects of medications that the patient can use and the signs characteristic of glaucoma, such as the Krokenberg spindle.

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

Gonioscopy

Gonioscopy is mandatory for all patients suffering from glaucoma. When examining, you should pay attention to the signs of the syndrome of pigment dispersion, exfoliative syndrome, as well as signs of recession of the anterior chamber angle. Gonioscopy should be performed annually, since the initially open angle of the anterior chamber of the eye can narrow with age, eventually leading to a chronic or, rarely, acute closure of the anterior chamber angle. Gonioscopy should be carried out after the beginning of application of miotics or after a change in their concentration, due to the fact that they can cause a pronounced narrowing of the anterior chamber angle. Scale of gonioscopic changes Specaf is a valuable clinical method that allows you to quickly quantify and fix the state of the angle of the anterior chamber of the eye.

Rear Pole

Primary open-angle glaucoma is initially a disease of the optic disc. A correct assessment of the condition of the optic nerve is an obligatory part of the examination and subsequent management of the patient with suspected glaucoma. Evaluation of the optic nerve is the most important aspect in the diagnosis of primary open-angle glaucoma. In the management of a patient with glaucoma, the status of the optic nerve disk is of secondary importance after careful collection of anamnesis.

To examine the optic disc is better with a wide pupil. After dilating the pupil, a stereoscopic examination of the optic nerve disk is carried out using a slit lamp and strong collecting lenses at 60 or 66 D. It is best to examine using a beam of light in the form of a narrow slit at high magnification (1.6 or 16X), using a slotted Haag-Streit 900-series lamp . With this method, the doctor gets an idea of the topography of the optic disc. Also measure the disc. To measure the vertical dimension of the disk, the beam of light is expanded until the horizontal dimension of the beam coincides with the width of the disk. Then the beam is vertically tapered until the vertical dimension of the beam coincides with the vertical diameter of the disk. Then, on the slit lamp scale, a value is noted which, after appropriate correction, corresponds to the vertical diameter of the disk. The values obtained are somewhat different when using the lenses Volk and Nicon. It is assumed that when using lenses in 60 D, the value on the scale is increased by 0.9, for lenses in 66 diopters correction is not required, and for lenses at 90 D, the value on the scale is multiplied by 1.3. The vertical diameter of the optic disc is normally 1.5-1.9 mm.

The next stage is a direct ophthalmoscopy. The ophthalmoscope light beam is narrowed so that the diameter of the projection spot on the retina is about 1.3 mm. This size corresponds to the beam mid-size on some ophthalmoscope Welch- Allyn and beam of small size in other Ophthalmoscope Welch-Allyn. The researcher must know the size of the ophthalmoscope beam that he uses. It can be calculated by projecting a spot of light on the retina next to the optic nerve disc, by comparing the vertical diameter of the spot and the vertical diameter of the disc, and then using strong collecting lenses to accurately measure the vertical spot size. Measuring the spot size once, it is possible to measure the optic disc with a single direct ophthalmoscope. When examining eyes with farsightedness or myopia more than 5 D, using a strong collecting lens, the disc will appear correspondingly more or less due to its optical magnification or reduction.

The examination of the optic disc is best done with a direct ophthalmoscope, when the doctor and patient sit opposite each other. The head of the doctor should not cover the other eye of the patient, because for the correct conduct of the examination the patient must clearly fix the position of the view with the help of another eye. First, attention should be paid to the optic disc at 6 and 12 h: the width of the neuroretinal girdle, the breakthrough of excavation or hemorrhage, peripapillary atrophy, displacement, curvature, plethora, narrowing or "bayonet" deformation of the vessels. It is also necessary to estimate the thickness of the girdle by 1, 3, 5, 7, 9 and 11 h by measuring the belt / disc ratio, which is calculated as the ratio of the thickness of the girdle to the diameter of the optic nerve along the same axis. Thus, the maximum value of the ratio of belt / disc is 0.5.

The area of the girdle in the absence of pathology is relatively unchanged. Thus, in the case when the patient has a large-sized disc, the belt is distributed over a much larger area (as shown above, the belt is part of the radius). It turns out that the thickness of a normal band of a large disk without pathology is less than the thickness of a normal belt of a small disc without pathology.

In young patients or in patients with glaucoma, in which the lesion of the disc is at relatively early stages (especially 0-III stages), it is useful to evaluate the layer of nerve fibers. The study is carried out using a direct ophthalmoscope by focusing light (preferably without the red part of the spectrum) on the surface of the retina and tracing the nerve fibers. In most cases, the topography of the optic nerve disc gives more valuable information than the condition of the layer of nerve fibers.

The optic nerves of the two eyes must be symmetrical. With asymmetry, almost always there is a pathology of one optic nerve in contrast to the situation where the optic nerves have different sizes

It is necessary to pay special attention to the breakthrough of the excavation of the disc - a local defect with a depth to the outer edge of the girdle from the temporal side near the upper or lower pole of the disc, a pathognomonic change for glaucoma. It should also pay attention to the presence of hemorrhages in the retina, above the girdle. Hemorrhages, as a rule, testify to the lack of control of the glaucoma process.

Special research methods

Investigating the field of view on a red object allows one to obtain data on the absence or presence of defects. Changes in the visual fields obtained with the Esteman test on the Humphrey perimeter provide valuable information about the functional changes associated with glaucoma. A mandatory survey method for assessing the damage to the visual field of each eye and confirming the absence of changes is a standard perimetry carried out monocularly, preferably using an automatic perimeter such as Octopus or Humphrey.

The disk damage probability scale is DDLS (the Disk Damage Likelihood Scale)

	The thinnest portion of the girdle (belt / disc relation)
DDLS	For a small disc <1.5 mm	For an average size disc of 1.5-2.0 mm	For a large disc> 2.0 mm	The DDLS stage
0a	0.5	0.4 or more	0.3 or more	0a
0b	From 0,4 to 0,5	From 0,3 to 0,4	From 0.2 to 0.3	0b
1	From 0,3 to 0,4	From 0.2 to 0.3	From 0.1 to 0.15	1
2	From 0.2 to 0.3	From 0,1 to 0,2	From 0.05 to 0.1	2
3	From 0,1 to 0,2	Less than 0.1	From 0.01 to 0.05	3
4	Less than 0.1	0 <45 °	0 to 45 °	4
5	The absence of a belt at <45 °	0 to 45 ° -90 °	0 to 45 ° -90 °	5
6th	No belt at 45 ° -90 °	0 to 90 ° -180 °	0 to 90 ° -180 °	6th
7th	No belt at> 90 °	0 to> 180 °	0 to> 180 °	7th

DDLS is based on an estimate of the thickness of the neuro-retinal band at its thinnest point. Calculate the belt / disc ratio equal to the ratio of the radial thickness of the band to the diameter of the disk along the same axis. In the absence of a belt, the belt / disc ratio is considered equal to 0. The length of the absence of the belt (the ratio of belt / disk is 0) is measured in degrees in degrees. Care should be taken to evaluate the thickness of the girdle and differentiate its true absence from bending, which may occur, for example, in the temporal parts of the discs in patients with myopia. The bend of the girdle is not considered his absence. Because the thickness of the belt depends on the size of the disc, it should be measured before using the DDLS scale. The measurement is carried out using lenses in 60 or 90 diopters using the appropriate correction. The Volk 66D lens distorts the size of the disc to a lesser extent. Correction for other lenses: Volk 60DxO, 88, 78Dxl, 2,90Dxl, 33. Nikon 60Dxl, 03, 90Dxl, 63.

 Diagnosis of glaucoma

Early detection and clinical examination of patients with glaucoma

Glaucoma is a disease of social importance. Only primary glaucoma affects about 1% of the population aged 40 years and older. This disease is one of the main causes of blindness. Glaucoma can not be completely cured, since it is a chronic disease, but one can prevent blindness from it if the disease is detected early and the patient is under constant medical supervision, receiving rational treatment. Early detection of patients with glaucoma is carried out by means of medical examination of the population. The examinations are divided into current and active. As a rule, current examinations are a survey of persons who come to a polyclinic but about any other disease. In the clinic they are held in the offices of pre-medical examination by nurses, who have eye tonometry, or in the eye cabinet.

The current examination is recommended to expose all patients over the age of 40 who have visited the eye room, as well as persons suffering from endocrine, cardiovascular and neurological diseases.

Active inspections are carried out directly at the enterprises where the doctor and nurse arrive, or by calling to the polyclinic on a special schedule elderly people living in a certain area or working in a particular enterprise.

Since the frequency of glaucoma is higher in relatives of patients with glaucoma and in persons with endocrine pathology (especially in patients with diabetes mellitus), this contingent with an increased risk of disease should be examined first.

It should be noted that active examinations require a lot of time and are not always effective. Such examinations are mandatory and systematically subjected to persons having contact with occupational hazards, and especially close relatives of patients with primary glaucoma.

Both types of profosmogra consist of two stages. The purpose of the first stage is to identify those who are suspected of glaucoma, the goal of the second stage is to make a final diagnosis. The second stage of the examination is carried out in a polyclinic, in a glaucoma cabinet or center, and in some cases - even in a hospital.

Every patient with glaucoma should be on a dispensary record. There are several links in the system of dispensary treatment. The first link is the supervision of the eye doctor, the second is the examination and treatment of the glaucoma in the doctor's office, the third is hospital treatment. It should be noted that the primary identified ballroom with glaucoma are recorded by the eye doctor. The patient with glaucoma should be called by the doctor to observe the visual functions at least once every 3 months with the obligatory examination of the visual fields. In cases where there is no compensation for intraocular pressure, a visit to the patients with an eye cabinet should be more frequent. If there are no glaucoma rooms in the city or region, dispensary observation of patients with glaucoma is performed by the doctor of the eye clinic of the polyclinic, and in case of indications - by the hospital. The role of the hospital in the system of dispensary care is to provide highly qualified diagnostic and therapeutic care for patients with glaucoma.

[25], [26], [27], [28], [29], [30], [31]

Treatment of glaucoma

Treatment of glaucoma consists of several directions:

1. hypotensive therapy - normalization of intraocular pressure;
2. improvement of the blood supply to the optic nerve and internal membranes of the eye - stabilization of visual functions;
3. normalization of metabolic processes in the tissues of the eye, to stop the dystrophy of the membranes. This also includes healthy working and recreational conditions, a healthy diet.
4. Surgical treatment (operation) of glaucoma.

Methods of antihypertensive treatment of glaucoma - myotics, cholinomimetics, anticholinergics - block the factors that cleave acetylcholine.

Glaucoma - Treatment

Modern operations used in glaucoma include:

1. improvement of outflow of intraocular fluid;
2. decrease in production of intraocular fluid.

If the development of intraocular fluid decreases, then innervation breaks down, corneal dystrophy develops, and so on. On the seeing eye, operations on the ciliary body are undesirable.

Glaucoma - Operations

Lifestyle for glaucoma

Most patients with glaucoma can lead a normal lifestyle, but some rules regarding nutrition should be followed.

Coffee Tea. Within an hour after consuming coffee or strong tea, there may be a modest increase in intraocular pressure, but this effect is so minimal that no patient with glaucoma ever refuses these drinks.

A glaucoma patient should not limit himself to the use of liquid, but it should be taken evenly throughout the day, you need to drink an adequate amount of liquid, but in small portions.

Alcohol. A small amount of alcohol, especially wine, is well tolerated and even has a beneficial effect on the heart and blood circulation. A patient with glaucoma can safely take spirits in small quantities even daily. In the case of an acute attack of closed-angle glaucoma, the acceptance of a large number of strong alcoholic beverages can cause a decrease in intraocular pressure for several hours, it is impossible to abuse etm.

Smoking is one of the most serious risk factors that threaten human health. Smoking also affects the occurrence of eye diseases. Thus, smokers are more likely to have eye diseases such as obstruction of the retina, muculopathy, cataract and others, and at an earlier age than non-smokers. In the elderly, smoking is a risk factor for the development of increased intraocular pressure.

Leisure and sports. Regular physical activity is as important for a patient with glaucoma, as is compulsory rest, sufficient sleep. Physical activity tends to cause a decrease in the eye pressure, except for cases of pigmentary glaucoma, in which physical activity increases intraocular pressure. Sports activities are also recommended for patients with significantly reduced blood pressure to stimulate and stabilize blood circulation. Patients who are already suffering from narrowing of the visual fields should be warned about their condition. They can only practice certain sports.

Diving. When diving with a mask, the oscillation of the intraocular pressure is insignificant. Patients who have a marked lesion of the optic nerve should refrain from scuba diving.

Sauna. Changing the level of intraocular pressure occurs in glaucoma patients as well as in healthy people: in the sauna it decreases, and then restored to its original level within an hour. But there is no evidence that the sauna can be useful for glaucoma.

Air flights. Usually aboard the aircraft, a rapid reduction in atmospheric pressure does not cause problems for glaucoma patients: there is an artificial atmospheric pressure inside the aircraft that compensates for a significant part of the natural pressure drop occurring at high altitude. The eye quickly adapts to the new situation. In this regard, a slight decrease in atmospheric pressure does not cause a significant increase in intraocular pressure. Nevertheless, patients suffering from glaucoma and expressed circulatory disorders and performing frequent flights should consult their ophthalmologist.

Music. The play on the wind instruments can lead to a temporary rise in the level of intraocular pressure. Patients with glaucoma who play these instruments should consult an ophthalmologist.