Glaucoma is the most common cause of irreversible loss of vision in the world. Damaging the nerve fibers of the fundus (base of the eye) of the eye, it usually progresses slowly but if untreated, it causes defects in the visual field and may even lead to blindness. The cause of the disease is not well known but the main risk factor is high pressure in the eye. There are at least 50 different types of glaucoma – it is not one particular disease but a group of diseases.
Glaucoma is most common in elderly (over 60 years) people and it rarely occurs in people who are younger than 40 years old. Exceptions to this are congenital (present at birth) glaucoma and some secondary forms of glaucoma (glaucoma caused by another disease).
Symptoms
In most patients, glaucoma develops slowly without giving any symptoms. However, if the pressure inside the eye is very high and the eye is not treated for the pressure, the fundus of the eye can be severely damaged within a few days. In the beginning, the patient does not notice the visual field defects because they typically develop slowly and from the peripheral parts of the visual field. By the time the patient notices any defects the disease has already advanced quite far. Glaucoma usually affects both eyes and because it progresses, glaucoma may, unless treated, lead to total blindness.
Risk factors
The most important risk factors of glaucoma are
High pressure in the eye: in most cases, the pressure in the eye increases because the outflow of the aqueous humor (which maintains the normal pressure in the eye) is impaired for some reason. A statistically normal pressure varies between 10 and 21 mmHg (millimeters of mercury). A slightly elevated eye pressure (22-30 mmHg) does not necessarily cause any defects in the visual field. But if the eye pressure is over 30 mmHg, the risk of glaucoma is 40-fold. However, the eye pressure of many glaucoma patients is below 21 mmHg (low pressure glaucoma), in other words, the pressure tolerance of ther nerve tissue of the fundus of the eye depends on the individual. The factors that do not depend on the eye pressure are still mostly unknown, but they are studied intensively.
Age: every decade of life doubles the risk of glaucoma.
Family history: if glaucoma occurs in the person's family, she/he is 3 to 9 times more likely to get glaucoma.
Exfoliation syndrome, which is common in the Nordic Countries. (grayish flakes on the surface of the lens, which can be detected by an ophthalmologist with a microscope).
Myopia (near-sightedness): in patients with myopia of over -3 diopters the risk of glaucoma is two- to three-fold.
Race: black people are about 5 to 6 times more likely to get glaucoma than Caucasians.
Certain other diseases: diabetes, artherosclerosis (hardening of the arteries), and hypertension (high blood pressure) may impair the blood flow in the eye and expose to glaucomatous defects.
Diagnosis
The vision loss caused by glaucoma is permanent. Therefore, it is important to find the disease as early as possible. If the disease is found early enough, treatment may be started even before any defects have occurred in the visual field. People who are over 40 years old should have their eyes checked regularly by an ophthalmologist (eye doctor) even if they do not have any symptoms.
Visit your eye doctor
no later than when you are 45 years old
when you are 45 to 60 years old, every 5 years
when you are over 60 years old, every 2 to 3 years
If you are nearsighted or if members of your family have glaucoma, it may be wise to have your eyes checked even more often.
To detect glaucoma, the patient’s eye pressure is measured. If considered necessary, the chamber angle and visual fields are studied, and the structure of the optic nerve is photographed with a special kind of camera. If the diagnosis is glaucoma, a pressure-lowering treatment should be started. If the pressure is high but there are no signs (pathological cupping of the optic disk and visual field defect) of glaucoma, it is more difficult to decide on the medicinal treatment. In such cases it is either possible to observe the situation without starting treatment or start prophylactic treatment. The solution is always individual and the most important factors behind the decision are the long-term eye pressure level and the other above-mentioned risk factors.
Treatment
Treating glaucoma is treating high eye pressure. The aim is to inhibit or at least slow the progression of the disease. The choices of treatment in the usual order are as follows.
Medicines
Laser
Surgery
There are several alternatives as far as medicinal treatment (typically eye drops) is concerned. Each patient’s medication is chosen individually considering the patient’s age and other diseases. The medicinal treatment of glaucoma usually lasts for the rest of the patient’s life. Due to long term treatment needed preservative free drops should be considered to ensure optimal tolerability of the medication. It is also essential that the medicines are used as advised by the doctor, because a medicine helps only if it is used properly. Laser treatment (laser trabeculoplasty) of the chamber angle aims at improving the outflow of the aqueous humor, and the pressure decreases in most patients, at least for a few years. If, despite other treatment, glaucoma progresses, surgical treatment may be used. There are different alternatives, but the result of the operation is not always permanent. In addition, cataract may develop as a complication of the procedure.
