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Glaucoma is an eye condition that is the second most common cause of blindness worldwide and affects a significant proportion of the general population. Prevention and early diagnosis are of utmost importance as they can prevent the unpleasant complications of this condition.
What is glaucoma?
Glaucoma is a disease of the eye, which gradually leads to damage to the optic nerve. It is mainly caused by increased pressure within the eye, resulting in decreased sensitivity of the ganglion, loss of peripheral vision and eventually total, irreversible blindness.
Glaucoma of the eye is usually an asymptomatic disease and glaucoma patients do not notice its presence. For this reason, early diagnosis of glaucoma is very important, as it prevents the occurrence of glaucomatous damage.
How is glaucoma caused?
The eye produces a fluid, the aqueous humour, which circulates through its various compartments and is eventually drained by the venous circulation.
If there is an obstruction to drainage, then the increased volume of the continuously produced aqueous presses on the walls of the eye, resulting in increased intraocular pressure. The pressure exerted on the fibres of the optic nerve gradually causes, by a complex mechanism, its irreversible destruction.
Glaucoma progresses slowly, over a period of years. It is a "silent" disease, since most patients in the early stages do not show any symptoms. Elevated intraocular pressure (usually above 20-22 mmHg) is the first indication of the disease, although there are rare cases of glaucoma with normal pressure.
What are the types of glaucoma?
The types of glaucoma are:
- Chronic open-angle glaucoma, the most common form of glaucoma. It occurs due to a disturbance in the balance of aqueous humor production - drainage, resulting in a gradual increase in intraocular pressure.
- Closed-angle glaucoma, in which access to the angle of the anterior chamber is closed, resulting in increased intraocular pressure. In the acute form of the disease, the increase in pressure is sudden, causes severe symptoms and requires immediate treatment.
- Secondary glaucoma. Intraocular pressure increases as a result of another eye disease.
- Congenital glaucoma. It is very rare, occurs in babies and young children and usually coexists with other eye abnormalities.
- Glaucoma of normal pressure. It occurs in people who have an optic nerve with very high sensitivity, capable of being affected by normal intraocular pressure values.
What are the predisposing factors?
There are several factors that have been associated with an increased likelihood of developing glaucoma. In particular:
- Age over 40 years old
- African descent
- Genetic factors / heredity
- Myopia
- Diabetes
- Long-term administration of cortisone, especially topical (eye drops)
- Eye injury
- Vascular diseases
- Eye inflammation
What are the symptoms?
Unfortunately, most of the time glaucoma does not give any symptoms. Either it is found accidentally during an eye examination, or the patient presents at the last stage of the disease with significant loss of visual field or vision.
Acute glaucoma is very different and causes a painful, red eye with reduced visual acuity. Some people also feel nauseous and faint. Coloured rings around the lights in dim light can be a warning sign of acute glaucoma.
How is the diagnosis made?
The eye examinations that are performed for the diagnosis and monitoring of glaucoma are:
- Taking a medical and family history
- Measurement of visual acuity
- Biomicroscopy
- Tonometer
- Checking the angle of the anterior chamber
- Checking the optic nerve with dowsing
It should be noted that the simple measurement of intraocular pressure is not sufficient for the detection of all cases of glaucoma, since about 15% of glaucoma cases do not show elevated pressure (low-pressure glaucoma).
In cases suspected of glaucoma, additional tests are performed:
- Field of view control
- Optic nerve scan (SLO)
- Optical coherence tomography of nerve fibres, macula and optic nerve
- Measurement of the blood flow of the optic nerve (BFA)
- Corneal pachymetry
How can glaucoma be treated?
The aim of treating glaucoma is to slow down the damage to the optic nerve fibres. Nerve fibres that have already been damaged, and the corresponding damage to the visual field, do not recover. The main way to treat glaucoma is to maintain low intraocular pressure by reducing the production of aqueous humor or increasing its drainage. This can be achieved by medication, laser applications, surgery or a combination of all of these.
Is there any prevention?
Unfortunately, the vision loss caused by glaucoma is irreversible. The disease may not be noticed until the last stages, when it is too late. For this reason, prevention through early diagnosis is vital. Everyone over the age of 40 needs to have an eye examination every 1-2 years, and in cases of a family history of glaucoma, screening should be done earlier, from the age of 35.
Bibliography
https://www.polyiatreiomedica.gr/υπηρεσίες/οφθαλμολογία/γλαύκωμα
https://www.ophthalmica.gr/pathiseis/glaukoma/
https://www.glaucoma-laser-eyecenter.gr/sygxroni-ofthalmologia/glaukoma/
https://drkalantzis.gr/παθησεισ/θεραπεια/γλαυκωμα.htm
https://www.athensvision.gr/glaucoma/
https://www.hygeia.gr/glaykoma-ola-osa-prepei-na-gnorizoyme/
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