Glaucoma – early detection guarantees the best treatment
What is glaucoma?
Glaucoma is the general term for a group of diseases that proceed unnoticed and that cause damage to the optic nerve. There is no cure for glaucoma yet and it can lead to blindness if it is not recognised and treated accordingly. In most cases the highest risk factor is an individually increased intraocular pressure, which is responsible for the development and progression of glaucoma. However, people with normal intraocular pressure can also develop glaucoma. Their eyes are either particularly sensitive or the blood supply to their optic nerve is insufficient. Nerve fibres die off in the course of the illness. As a result, there are partial losses to the field of vision that only become noticeable when there is massive damage to the optic nerve. The central vision acuity only diminishes or ceases completely at this stage. The loss of nerve fibres is irretrievable, yet further loss can be prevented. The affected patients at first do not realise they are suffering from glaucoma as they experience neither pain nor visual distortions.
The most frequent type of glaucoma is open angle glaucoma with few symptoms, which patients only recognise at a late stage. Another type of open angle glaucoma is normal pressure glaucoma in which there is no excessive intraocular pressure. With angle-closure glaucoma (acute glaucoma, glaucoma seizure), the intraocular pressure increases quickly and reaches high levels. As opposed to the other types of glaucoma, in this case there are typically acute symptoms such as intense pain, visual impairment and nausea. Secondary glaucoma, such as PEX glaucoma (pseudoexfoliation glaucoma) is caused by another eye or general illness.
Glaucoma is the second most prevalent cause of blindness around the world, irrespective of the level of development of the country concerned. The risk of developing glaucoma increases with age. This is why regular check-ups starting at the age of 40 are important for the early detection of glaucoma formation. When detected early, the course of a glaucoma can be slowed down with eye drops or surgery.
Answers to key questions
Glaucoma – causes and risk factors
Glaucoma damages the optic nerve. This damage can be the outcome of increased intraocular pressure (ocular hypertension), which is considered to be the major risk factor for glaucoma. An increase in the intraocular pressure will not necessarily damage the optic nerve or require treatment. The risk of ocular hypertension turning into glaucoma within five years is ten per cent.
In addition to increased interocular pressure, blood supply seems to also play a part. Especially with a normal pressure glaucoma, doctors assume that the nerve fibres are not supplied with enough blood due to highly fluctuating or too low blood pressure. Similarly, a vasospasm where a blood vessel suddenly and spasmodically is restricted also damages the eye.
The intraocular pressure is determined by the production and drainage of the aqueous humour in the eye. The aqueous humour plays a key function in the eye by supplying the lens and the cornea with nutrients. With glaucoma the drainage of the aqueous humour is disrupted. It accumulates inside the eye and the intraocular pressure increases. After a certain time the optic nerve is damaged mechanically.
In addition to increased intraocular pressure, other risk factors for the development of glaucoma include increased age, a glaucoma condition among first-degree relatives or extreme short-sightedness.
What are the typical symptoms?
Open angle glaucoma occurs mostly in elderly individuals and does not cause any directly discernible symptoms in its initial stages. Central visual acuity remains almost unchanged and defects on the edges of the field of vision go unnoticed. People with the condition often no longer see their surroundings fully. For example, they do not see steps or objects that they do not directly focus on or that are at the edges of their field of vision. As the perception of obstacles is primarily controlled by the field of vision and not by the central visual acuity, they often fall and their ability to drive is also diminished.
With closed angle glaucoma there is a sudden and sharp increase of the intraocular pressure accompanied by impaired vision, piercing pain and nausea. This is an acute emergency.
How does a glaucoma condition progress and how is it diagnosed?
The most frequent type of glaucoma, open angle glaucoma, progresses gradually and is only noticed by patients when the losses in the field of vision are very noticeable. If it remains untreated, the eye can become blind. This is why regular check-ups after the age of 40 are particularly important, as an early diagnosis allows the treatment of risk factors such as increased intraocular pressure and prevents progression of the illness.
The condition is diagnosed by an ophthalmologist. Initially the intraocular pressure is measured. Then the ophthalmologist assesses the state of the optic nerve through the pupil in a painless process. If there is suspected glaucoma, then a field of vision (perimeter) examination becomes necessary to detect loss of vision in the field of vision outside the visual centre. Imaging methods, such as the Heidelberg Retina Tomography (HRT) for the depiction of the optic nerve papilla or Optical Coherence Tomography (OCT) for measuring the nerve fibre thickness around the optic nerve papilla provide precise, three-dimensional images that allow damage and the course of the illness to be assessed.
How can glaucoma be treated?
Eye drops that lower the intraocular pressure (glaucoma medications) containing different active ingredients such as prostaglandin analogues, beta-blockers, alpha agonists or local carbonic anhydrase inhibitors can be used to treat glaucoma. They are generally the first choice of medications to prevent further damage to the optic nerve or to slow down the course of the illness. As glaucoma therapy is a long-term therapy, anti-glaucoma medication without preservatives is the better choice. If glaucoma treatment with medication is not enough, then laser surgery or operations are additional treatment options.
Can a glaucoma condition be prevented?
Unfortunately, there is no guaranteed way to prevent glaucoma. This is why early detection based on regular examinations by an ophthalmologist is very important. This also allows the detection and treatment of the early phases that go unnoticed by the patient to prevent subsequent damage to the optic nerve.