GLAUCOMA

From Big Medical Encyclopedia

GLAUCOMA (grech, glaukoma) — the disease of eyes, the main manifestation to-rogo is increase in intraocular pressure. Hippocrates used the term «glaukosis»; Aristotle offered the term «glaukoma» for designation of the whole group of eye diseases. In modern value the term «glaucoma» began to be applied with 60 — the 70th there are 19 century when the leading role of increase in intraocular pressure in a pathogeny and symptomatology of a disease was recognized.

Consider compensated if intraocular pressure (at measurement by a tonometer weighing 10 g of Maklakov) does not exceed 28 mm of mercury., subcompensated — with a pressure of 28 — 35 mm of mercury. and noncompensated — with a pressure over 35 mm of mercury. However question of individual norm intraocular pressure (see) it is insufficiently studied. Not less important indicator is the size of daily fluctuations of intraocular pressure. Normal it reaches the maximum values in early morning, and minimum — in the evening. Adverse it is necessary to consider fluctuations higher than 5 mm of mercury., even if absolute values of intraocular pressure do not exceed 28 mm of mercury.

It is accepted to subdivide G. on primary and secondary. At primary G. the disturbance of regulation of intraocular pressure which is expressed in its increase leads to emergence and development of other symptoms of a disease. At secondary G. increase in intraocular pressure is a direct consequence of other disease (e.g., an iridocyclitis, an incomplete dislocation of a crystalline lens, an injury of an eye, fibrinferments of a cavernous sine, etc.). Such division is quite justified clinically, but is theoretically disputable. The symptom of hypertensia of an eye, in effect, is always secondary as stand behind it (at least and not diagnosed) these or those reasons causing disturbances of normal circulation of intraocular liquid.

Primary Glaucoma usually develops 40 — 50 years are aged more senior; strikes apprx. 2% of the population of this age group. In the Soviet Union and in the majority of other developed countries of the world of G. is on the first place among the reasons of an incurable blindness.

Primary G.'s etiology is not clear.

The pathogeny and pathological anatomy

In most cases increase in intraocular pressure is caused by disturbance of outflow of intraocular liquid. The place of disturbance of outflow at primary G. is the space of an angle of iris (a corner of an anterior chamber of an eye) where the so-called filtering zone of an eye is located. Obstacles result from blockade of access to outflow tracts or changes in outflow tracts. In turn access to outflow tracts can be blocked by a root of an iris (the most frequent option), the commissures (goniosinekhiya) or residual fabric developing here (e.g., as a result of the wrong embryogenesis).

Changes in outflow tracts most often concern an internal or outside wall of a venous sine of a sclera (a shlemmov of the channel) in this connection speak about trabecular or intrascleral localization of defeat. There are data indicating a possibility of fall (collapse) of a venous sine of a sclera (A. P. Nesterov). Some authors acknowledge the possibility of existence of hyper secretory G. owing to hyperproduction of intraocular liquid.

Is not subject to doubt that behind all these local factors of disturbance of circulation of intraocular liquid (see. Hydrodynamics of an eye ) deeper frustration lie. Development of blockade of an angle of iris by a root of an iris is promoted substantially by constitutional features of a structure of an eye (too big crystalline lens, its front arrangement etc.).

The pathogeny of changes in outflow tracts of the filtering zone is yet not quite studied; noted disorders of fabric metabolism appear, apparently, as a result of neurovascular disturbances. Considerably they represent big, than usually, extent of age changes. Difficulties of outflow of intraocular liquid can remain a long time compensated, hl. obr. due to reduction of products of intraocular liquid. However in situations of a stress balanced state can easily be broken (e.g., cases of a bad attack of G. at an emotional injury, overfatigue etc.). Various pathogenetic elements of eye hypertensia can accumulate at each other. So, e.g., blockade of an angle of iris a root of an iris is functional in the beginning; it can lead to development of goniosinekhiya and blockade of organic character. Existence of hereditary predisposition by is proved.

Increase in intraocular pressure at secondary G. is caused by the same disturbances, as at primary G.: a delay of access to outflow tracts of intraocular liquid (e.g., exudate), changes of outflow tracts (e.g., as a result of inflammatory process and scarring), hyperproduction of intraocular liquid, etc.

Owing to a community of final pathogenetic links of a disease the border between primary and secondary G. cannot be considered absolute; with improvement of diagnosis even more often it is possible to establish the reasons leading to changes in ways of circulation of intraocular liquid.

As a result of hypertensia of an eye disturbance of blood circulation in vessels of an optic nerve, retina and horioidea develops. As a rule, both eyes, often not at the same time get sick.

Classification

In 1952 at the All-Union meeting on G. was accepted G.'s classification, three signs are the basis a cut: clinical form, stage and extent of compensation of process.

In 1975. The All-Russian congress of ophthalmologists accepted new classification of.

On this classification distinguish three forms G.: closed-angle, open-angle and mixed. In turn each of these forms can have defined stages: initial (I), developed (II), far come (III) and terminal (IV). The condition of intraocular pressure on the accepted classification is estimated as normal, moderately raised and raised, and dynamics of visual functions — stabilized or not stabilized.

Fig. 1. The scheme of an angle of iris (a corner of an anterior chamber) of a healthy eye (it is specified by an arrow); at the left — histologic, on the right gonioskopichesky: 1 — a cornea; 2 — a front boundary plate; 3 — cutting; 4 — a zone of an edge linking of an angle of iris and a venous sine of a sclera; 5 — a back boundary plate; 6 — a strip of a ciliary body; 7 — a root of an iris; 8 — a pupil; 9 — a crystalline lens; 10 — a ciliary corbel (a tsinnova a sheaf); 11 — ciliary shoots; 12 — a ciliary muscle; 13 — venous network of a sclera.
Fig. 2. Different types of an angle of iris (are specified by shooters) at glaucoma (at the left — histologic, on the right — the gonioskopichesky pictures corresponding to them): 1 — an angle of iris wide, in the drawing all gonioskopichesky reference points (see fig. 1) and the structures of a corner of an anterior chamber corresponding to it are visible on the right (see fig. 1 at the left); 2 — an angle of iris of average width, in the drawing the forefront of a ciliary body (fig. 1, 6) and a back boundary plate (fig. 1, 5) is not visible on the right; 3 — an angle of iris narrow, in the drawing the most part of an edge sheaf (fig. 1, 4 and 5) which is closed by a root of an iris (fig. 1,7) is not visible on the right; 4 — the angle of iris is closed, in the drawing only the front boundary plate (fig. 1, 2) is visible on the right. Degree of visibility of zones of an angle of iris of an anterior chamber of an eye at a gonioskopiya depends on a vystoyaniye of a root of an iris.

Besides, are allocated: a bad attack of primary G. and suspicion for. Definition of a form G. on new classification demands an obligatory research of area of an angle of iris (a corner of an anterior chamber of an eye — tsvetn. fig. 1 and 2) at each sick G. (see. Gonioskopiya ).

To glaucoma of an open corner usually there corresponds the wedge, simple and chronic congestive G.'s picture, glaucoma of the closed corner — to a bad attack of. In general, however, there is no full parallelism between a wedge, G.'s manifestations and a gonioskopichesky picture.

A clinical picture

According to the classification accepted in 1952 allocate simple and congestive Forms.

Simple glaucoma it is characterized by three main symptoms: increase in intraocular pressure, decrease in visual functions (first of all narrowing of a field of vision), excavation (patol, deepening) optic disk. The second and third symptoms of a triad are the investigations of the first and develop later.

Disturbance of visual functions begins, as a rule, with changes of a peripheral field of vision (its narrowing from a nose), and also with increase in a blind spot. Later the central sight suffers. At moderate narrowing fields of vision (see) tell about the developed G., at expressed (15 ° and more at least in one meridian) — about far come. Further, during the progressing of a disease, there is only photoperception, i.e. almost absolute G.; absolute G. (terminal G.) is characterized by full loss of visual function. At the started G. when visual functions are already lost, on the foreground the pain syndrome — absolute hurting can act.

Fig. 3. Physiological deepening (excavation) of an optic disk (1); 2 — not profound part of an optic disk.
Fig. 4. Glaukomatozny deepening of an optic disk and its gray atrophy.

Excavation of an optic disk is manifestation of an atrophy of nerve fibrils (tsvetn. fig. 3 and 4); it usually develops along with emergence of resistant defects under review.

Visual disturbances at simple G. can develop so gradually that sick their long time does not notice (up to a total blindness of one of eyes).

Congestive glaucoma. In addition to the listed symptoms, at congestive G. changes from a front piece of an eye are noted (a small anterior chamber, hypostasis of a cornea, decrease in its sensitivity, a tendency to a mydriasis, overflow of front ciliary vessels blood, etc.). These changes are the cornerstone of a number of subjective frustration: passing misting of sight, iridescent circles around light sources, unsharp pains in a circle of an eye and in a temple.

Bad attack of glaucoma represents a complex of the objective and subjective symptoms inherent to congestive G., but extremely sharply expressed. The attack is quite often provoked by a neuroemotional stress (see. Emotional stress ), and also mydriasis (stay in the dark, accidental instillation of midriatik, etc.). Intraocular pressure is increased, in some cases reaches 80 mm of mercury. above. Sight sharply falls and can disappear is irreversible within several days or even hours. An eye is sharply hyperemic. The anterior chamber small or is absent. The pupil is expanded (the form of vertically extended oval is characteristic). Because of puffiness of a cornea it is often impossible to carry out an oftalmoskopiya. Eye pains and a headache are extremely severe and often do not disappear under the influence of morphine. The general phenomena can be noted: nausea, vomiting, dizziness, delay of pulse, synalgias which can be a reason for the wrong diagnosis of stenocardia, frustration of cerebral circulation etc. The postponed bad attack of G., as a rule, leaves the atrophic centers in an iris, resistant is sometimes observed mydriasis (see), a phacoscotasmus etc.

the Diagnosis

for diagnosis initial forms G. and mezhpristupny states at G. proceeding in the form of periodic bad attacks can present Difficulty. The huge number (more than 100) tests for early diagnosis of glaucoma is known. Major importance in a wedge, practice have a research of daily fluctuations of intraocular pressure, topography (see), an elastotonometriya, load tonometric tests (see. Tonometriya ), and darkness, reception of plentiful amount of liquid, a midriatika, low position of the head etc. can be a factor of loading.

It is extremely important to define a pathogenetic form of a disease, in particular to find out, G. belongs to the category of the opened or closed corner (see. Gonioskopiya ), since it defines the choice of an optimum method of surgical treatment.

Treatment

In drug treatment of G. the forefront is come so-called miotic (narrowing a pupil) by Cholinomimetic and antikholinesterazny means. Treat the most widespread means of the first group Pilocarpinum (0,5 — 6% solution, drops, from 1 to 6 times a day), Carbacholinum (0,5 — 1% solution, drops, to 6 times a day), aceclidine (2 — 5% solution, drops, to 6 times a day). Among antikholinesterazny means salicylate (0,25 — 1% solution, drops, to 4 times a day), prozerin (0,5% solution, drops, to 4 times a day), a demekariya bromide (Tosmilenum, 0,125 — 1% solution, drops, once a day), and also group of organophosphorous connections — Phosphacolum (0,01 — 0,02% solution), Arminum (0,005 — 0,01% solution), a pirofos (0,01 — 0,02% solution), etc. is most often used Eserinum.

The important place in G.'s therapy borrow also adrenomimetichesky means as, e.g., adrenaline (1 — 2% solution), ephedrine (2 — 5% solution). They are usually dug in by 2 times a day. Due to the mydriatic action of adrenomimetichesky means a necessary condition of their use is gonioskopichesky control: at a narrow angle of iris of an anterior chamber the mydriasis can strengthen blockade of an angle of iris and lead to increase in intraocular pressure. There are data on hypotensive effect of sympatholytics. Drugs of the listed groups can be used in various combinations.

Among drugs of a systemic effect at G. the most important place is taken by the inhibitors of coal anhydrase reducing products of intraocular liquid. Treat them, e.g., Diacarbum (Diamoxum, acetazoleamide, Fonuritum) on 0,125 — 0,25 g of 1 — 3 time a day. The main contraindication — tendency to acidosis, Addison's disease, cholelithic and pochechnokamenny diseases, acute diseases of a liver and kidneys.

At a bad attack of G. it is necessary to stop perhaps quickly an attack in order to avoid irreversible vision disorders. In this case adrenomimetichesky and adrenolytic means are, as a rule, contraindicated. The most intensive care is carried out by miotocs. Except inhibitors of a karboangidraza, the active osmotherapy is shown. For this purpose appoint glitserol (mix of glycerin with the same amount of fruit juice or syrup, inside at the rate of 1,5 g of glycerin to 1 kg of weight of the patient), urea (30 — 50% solution in sugar syrup in a dose of 0,75 — 1,5 g on 1 kg of weight or intravenously 30% solution of urea in 10% solution of glucose, kapelno in the same dose with a speed of 40 — 80 thaws a minute). With the same purpose intravenous administration of hypertensive solution of sodium chloride, salt laxatives inside is shown. On a temple on side of a sore eye put 2 — 3 bloodsuckers. At severe pains give analgetics.

G.'s treatment should be carried out under control of a daily curve of intraocular pressure. In the absence of compensation of glaukomatozny process surgical treatment is shown.

The conducting place in G.'s surgery is taken by so-called fistuliziruyushchy operations at which in a wall of an eyeglobe the opening (fistula) for constant drainage of a cavity of an eye and recovery of outflow of intraocular liquid becomes. Operation has the greatest distribution iridenkleyzisa (see), at a cut fabric of an iris is restrained in the fistulizatsionny channel. Fistuliziruyushchy operations have high hypotensive effect, however quite high injury and essential risk of postoperative complications are inherent to them.

At G. with blockade of an angle of iris of an anterior chamber a root of an iris (closed-angle G.) it is shown corectomy (see); it is method of the choice and at a bad attack of. At organic (sinekhialny) blockade of an angle of iris of an anterior chamber operation has the directed unblocking effect iridotsikloretraktion (see). At blockade of an angle of iris of an anterior chamber residual fabric (especially at inborn G.) showed a goniotomy (see. Goniotomy , goniopuncture). Disturbances in intramural outflow tracts (at G. with an open corner of an anterior chamber) demand surgical intervention on internal or outside walls of a venous sine of a sclera — sinusotomy (see), trabekulotomiya, trabekulektomiya (see).

New types of operations with use entered practice lasers (see) — laser corectomy, a laser goniopuncture, laser cyclo-coagulation (M. M. Krasnov).

At the absolute hurting G. it is necessary to resort to an injection of alcohol for an eyeglobe, roentgenotherapies on area of an eye, operation of an optiko-tsiliarny neurectomy or even to removal of an eye (see. Enucleation of an eye ).

At secondary G. treatment shall be directed first of all to a basic disease (inflammatory process in a choroid of an eye, dislocation of a crystalline lens or disturbance of an integrity of its capsule etc.). For the rest it is necessary to consider that the proximate causes leading to developing of eye hypertensia at primary and secondary G. same: it defines also a community of the principles to lay down. influences.

The forecast

the Forecast serious concerning sight. At not treated G. sight falls up to a blindness. Timely and correct drug and surgical treatment for long time keeps visual functions.

Prevention

In prevention of a blindness at G. is of great importance early diagnosis. In a number of the cities and the republics mass routine maintenances on G. of persons are performed 40 years are more senior (see. Medical examination ). Practice of so-called night hospitals is repaid, at a cut measurement of a daily curve of intraocular pressure is performed in the conditions of usual for inspected activity within a day. For G.'s identification active examinations of organized groups of the population are conducted. To people 40 years, seeing the oculist are more senior, measure intraocular pressure irrespective of the reasons of the address.

See also Hydrophthalmia .


Bibliography Broshevsky T. I. and Tokareva B. A. Inborn children's glaucoma and its treatment, M., 1971, bibliogr.; To l I am a h to about M. L. Glaukom of children's, youthful and young age, M., 1970; Krasnov M. M. Microsurgery of glaucomas, M., 1974-, bibliogr.; The multivolume guide to eye diseases, under the editorship of V. N. Arkhangelsky, t. 2, book 2, M., 1960; The Guide to eye surgery, under the editorship of M. L. Krasnov, M., 1976; Becker B. Diagnosis and therapy of the glaucomas, St Louis, 1970; D u k e-E 1 d e r S. a. J and V. have Glaucoma and hypotony, in book: System of ophthalmology, ed. by S. Duke-Elder, v. 11, p. 377, L., 1969, bibliogr.; Leydhecker W. Glaukom, B., 1973; T r e v o r-R o p e of P. D. The eye and its disorders, Oxford, 1974.

M. M. Krasnov.

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