Glaucoma

The term “glaucoma” is used to refer to a group of diseases characterized by lesion ( neuropathy ) of the optic nerve and change (loss) of visual fields, usually associated with increased intraocular pressure.The defeat of the optic nerve leads to irreversible loss of vision, therefore, early diagnosis and timely treatment of glaucoma are very important.

Glaucoma is one of the leading causes of blindness.Late diagnosis is the main cause of blindness in glaucoma.

Intraocular pressure

The main risk factor for glaucoma is an increase in intraocular pressure.In normal intraocular pressure is 11-21   mm   Hg   senior, average – 15.5   mm   Hg   st.Apparently, the risk of blindness is directly proportional to the degree and duration of the increase in intraocular pressure.However, up to 20% of patients with characteristic changes in the optic nerve and visual fields have normal intraocular pressure.Apparently, other factors, such as vascular spasm, contribute to damage to the optic nerve in these patients.

The level of intraocular pressure is affected by many factors.Intraocular pressure changes during the day and is often higher in the morning.These fluctuations in intraocular pressure depend on individual circadian rhythms and can vary greatly from person to person.Intraocular pressure rises slightly when a person lies on his back.

With arterial hypertension, intraocular pressure rises only slightly, but it can be reduced by prescribing antihypertensives, such as beta-blockers and calcium antagonists.There is no consensus regarding the effects of caffeine, smoking and exercise on intraocular pressure.There is also a small group of people who are sensitive to glucocorticoids .Their intraocular pressure may increase significantly in response to systemic or local (as part of the eye drops) use of glucocorticoids .Occasionally, such a reaction is caused by the application of creams or ointments containing glucocorticoids on the skin around the eyes.

Other risk factors

Today, the role of heredity in the development of many types of glaucoma is obvious, and any person with glaucoma in the immediate family (parents, brothers and sisters) should be considered at risk, especially after 40   years old.In addition, the risk of glaucoma increases with diabetes, high myopia, arterial hypertension, cardiovascular diseases.

Complaints

Early and moderate primary open – angle glaucoma is often asymptomatic.Only with a pronounced lesion of the optic nerve, patients sometimes notice blurring or blurring of vision.In rare cases, they notice a loss of peripheral vision;in order to detect a visual field defect, it is usually necessary to close the better seeing eye.Patients with intermittent angle-closure glaucoma may complain of eye pain or rainbow circles around light sources.In addition, an angle-closure glaucoma may be accompanied by nausea and vomiting.

Since some symptoms may be mild, absent, or masked by common symptoms, a thorough eye examination is important.

Diagnostics

1. Measurement of intraocular pressure. Intraocular pressure is measured by determining the force required to depress the cornea. Most often it is measured by a contactless air-jet tonometer. The advantages of this method include the absence of the need for anesthesia and the low probability of infection transmission, since the cornea is concerned only with the air stream.
2. The study of visual fields. To identify the narrowing of the visual fields, you need special equipment. Ophthalmologists often use automated perimeters, which, when used, impose a patient with light sources with adjustable brightness in standardly defined positions of visual fields.
3. Changes in the optic nerve head. The optic nerve head can be seen with a direct ophthalmoscope, even without pupil dilation.

Forms of glaucoma

Two forms of pathology are known – open – angle glaucoma and angle-closure .And in fact, and in another case, the result of pathological processes in the tissues of the eye becomes the death of the optic nerve, leading to blindness.In our eyes, a watery fluid continuously forms, the outflow of which occurs through an opening between the cornea and the iris (filtering angle).

Due to the balance of the influx and release of moisture inside the eyes, a special constant pressure is maintained.If, due to various reasons, the outflow of intraocular fluid becomes difficult, it begins to accumulate, which leads to an increase in pressure.As a result, the optic nerve and other nearby tissues begin to experience a constant load, the blood supply is disturbed, hypoxia occurs, and the person loses sight.

With open-angle glaucoma, the filter angle remains as wide and open as it should be, and obstruction of moisture release occurs in the deeper layers of the eye. This form of the disease develops slowly, gradually. With angle-closure glaucoma, the bypass channel is abruptly blocked, i.e. the angle of the front camera becomes closed. In this case, the intraocular pressure increases rapidly, there may be an acute attack, requiring immediate assistance.
 

Treatment  

With all the variety of glaucoma, there are only a few ways to reduce intraocular pressure.They are used consistently as the disease worsens.

Begin with the use of eye drops, reducing intraocular pressure.These drugs inhibit the production or increase the outflow of aqueous humor.Sometimes use a combination of several drugs.Often prescribed beta-blockers can have a side effect on the cardiovascular system and bronchi.

When drugs no longer reduce intraocular pressure, they resort to trabeculoplasty with an argon laser. The intervention is carried out on an outpatient basis. The first time it gives the effect in almost 80% of patients. Unfortunately, after 5   In about half of the successfully treated patients, intraocular pressure rises again.

Operations that create a path of outflow of aqueous humor from the anterior chamber of the eye under the conjunctiva, effectively reduce the intraocular pressure.The operation is successful in 85-90% of cases, but sometimes causes severe complications, including the formation of cataracts.Surgical treatment can reduce the dose of drugs or cancel them.In addition, the effectiveness of such treatment does not depend on how conscientiously the patient fulfills the doctor’s instructions.Surgical treatment is most often carried out with the failure of drug and laser treatment.

Prognosis and prevention of glaucoma

Modern methods of ophthalmology cannot ensure the complete recovery of patients with glaucoma, but treatment is necessary, since this pathology is characterized by a progressive course and leads to irreversible loss of vision in the terminal stages of the disease.The prognosis for glaucoma in the early stages is favorable for life and performance.The basis for determining the group of disability is a sharp decrease in visual acuity.

Prevention It comes down to regular examination by an ophthalmologist of patients over 40 years of age, as well as all persons entering the risk zone. All patients with an established diagnosis of “glaucoma” should be in the dispensary and attend an ophthalmologist 1 time in 2-3 months.