What is glaucoma?
Glaucoma or glaucoma is a group of eye diseases that usually go unnoticed for a long time, but damage the optic nerve and permanently impair vision. In the worst case, the eye goes blind. Both eyes can become ill (with a time delay).
The main risk factor for glaucoma is an individually elevated intraocular pressure. Most of the associated glaucomas are those with an open chamber angle in the eye, in so far as open-angle glaucomas are mentioned. Primary open angle glaucoma predominates.
Normal intraocular pressure is 10 to 21 mmHg.
Less than half of chronic glaucoma in Western countries is known to affected patients. When optic nerve damage becomes apparent, more than a third of vision may be lost. Often there is an impairment, in which the visual field is narrowed arcuately from the outside.
In other words, within one or more areas of the retina with normal photosensitivity of the visual cells, this decreases significantly, objects are no longer perceived. This can, for example, lead to orientation problems in the environment or in traffic. In the further course, failures to the central field of vision, towards the center of the gaze, are possible. Of the approximately 10,000 people who go blind in Germany every year, around 2,000 have glaucoma.
An angle block (“glaucoma case”) on the other hand is an acute clinical picture with severe pain, redness and visual disturbances of the affected eye. Often there are also marked concomitant symptoms such as headache, nausea and vomiting. Because of the danger of blindness, a glaucoma case is always an emergency, which belongs immediately in the hand of the ophthalmologist.
Glaucoma: early detection, diagnosis
Early detection for glaucoma is recommended from the age of 40 years. Intraocular pressure should be checked approximately every three years, and people aged 65 and over every one to two years. In particular with increased Glaucoma risk regular checks are recommended. The investigations include:
- An eye test
- Measurement of intraocular pressure (tonometry)
Assessment of the optic nerve (funduscopy): The ophthalmologist can assess the optic nerve head by mirroring the fundus through the pupil
Review of the visual field
All these examinations are paid by the health insurance companies only in case of suspected glaucoma. Because the glaucoma screening at the ophthalmologist is currently a so-called IGeL performance: an individual health care, for which the patient has to pay.
Therapy of glaucoma
For the treatment of glaucoma there are good effective drugs in the form of eye drops. If used regularly and correctly as prescribed by the doctor, they can lower intraocular pressure and stop or stop the progression of the disease. New delivery systems with drugs for insertion into the eye are currently under investigation. Maybe they can replace the tedious drop in the future.
An intervention with the laser or an eye operation is usually only required for very pronounced clinical pictures. New surgical techniques (so-called minimally invasive glaucoma surgery) also expand the treatment options . Congenital glaucoma is usually operated on.
- Causes and Types of Glaucoma
- Primary glaucomas (causes unknown, risk factors known)
- Intraocular pressure increased:
- Open or wide angle glaucoma
- Angular block / angle block glaucoma
- Congenital glaucoma
Intraocular pressure less than 21 mmHg:
- Normal tension glaucoma
- Secondary glaucoma (special causes)
- Increases intraocular pressure (generally open angle glaucoma):
- Pseudoexfoliation glaucoma (PEX glaucoma)
- Pigment glaucoma (deposits in the chamber angle)
- Glaucoma due to newly formed vessels (neovascular glaucoma, for example in diabetes)
- Inflammation, injuries, medication
- Congenital glaucoma
Intraocular pressure too high, optic nerve and visual field normal, increased risk of glaucoma
Primary glaucomas: open-angle glaucoma and angle-closure glaucoma
Glaucoma, which occurs spontaneously without any specific cause, is called primary glaucoma. In addition to the frequent wide-angle or open-angle glaucoma, this also includes the rarer angle-block glaucomas.
Info: In the chamber angle of the eye, the aqueous humor flows through a network of tissues (trabecular meshwork) and a small collecting channel into the bloodstream. The aqueous humor builds up the intraocular pressure. If the outflow is obstructed in the chamber angle, the intraocular pressure rises – in the long term, a glaucoma can develop.
The following graphic illustrates the process in three pictures.
The chamber angle in the eye also plays an important role in the treatment of glaucoma.
In addition to increased intraocular pressure, glaucoma also affects diminished optic nerve blood flow. Risk factors of primary open-angle glaucoma include glaucoma in first-degree relatives, over sixty years of age, and higher-grade myopia.
Special form: normal pressure or low pressure glaucoma
A special form of primary open-angle glaucoma is the so-called normal or low-pressure glaucoma. Here, damage to the optic nerve occurred, although the intraocular pressure is in the normal range. The affected eyes are more sensitive to “normal pressure”.
Acute angle block
If the outflow of aqueous humor is suddenly hindered in an overly tight chamber angle, an acute angle block (“glaucoma case”) occurs. The intraocular pressure is greatly increased. Chronic angle-closure glaucoma with damage to the optic nerve can arise as a result of an insufficiently treated angle block, for example due to adhesions in the chamber angle. In Europe, however, that rarely happens.
Glaucomas with special causes (secondary glaucoma)
If glaucoma occurs as a result of another illness or injury to the eye, or as part of a general condition, secondary glaucoma is present.
Pseudoexfoliation glaucoma (PEX glaucoma)
The most common form of all secondary glaucomas is pseudoexfoliation glaucoma (PEX glaucoma). The finest particles deposit on all structures of the anterior segment, including the lens and pupil margin. This is due to a hereditary disorder of the fibrous elements of the connective tissue. Since PEX glaucoma can sometimes progress relatively quickly, it is crucial to early diagnosis and treatment. Then the clinical picture can often be satisfactorily controlled.
Glaucoma due to certain drugs
Some medicines may also trigger secondary glaucoma. This includes, for example, cortisone.
More about the different forms of glaucoma in the chapter “Glaucoma: causes and risk factors” (see link above) in this article.
Congenital glaucoma may be present at birth or until early adulthood. Childlike glaucoma also distinguishes primary and secondary forms. Depending on the type of glaucoma, external signs may guide the suspect early on.
Increased intraocular pressure without glaucoma
There is also this: The intraocular pressure is increased, but the eye findings (optic nerve, visual field) is normal. However, the risk of developing glaucoma is ten percent per five years.