Scotoma

A scotoma describes the weakening or even loss of part of the visual field. Visual perception is limited or suspended in this area. Several forms of the scotoma can be differentiated, depending on the place of origin and the severity of the defect. The cause can lie in the area of ​​the eye, the visual pathway or the visual center.
Visual field perimetry is used to confirm the diagnosis of the scotoma.
Therapy and prognosis differ depending on the underlying disease. In any case, if such symptoms occur, you should immediately consult an ophthalmologist, because the earlier the diagnosis and therapy start, the better.

Causes of the scotoma

There are many different causes of a scotoma, which can be in the area of ​​the eye, the visual pathway or the visual center. Possible causes are:

• Diseases of the retina (e.g. retinal detachment)
• Diseases of the visual pathway or the visual center in the brain (e.g. intracranial mass)
• Optic nerve damage (e.g. in papillitis or retrobulbar neuritis)
• Chronic glaucoma (scotomas that increase over the years)
• Migraine (causes temporary scotomas such as ciliated scotoma, occurs suddenly, but usually resolves completely within a relatively short time)
• stress
• stroke

stress

Stress is known to have different effects on the body. Among other things, it can also influence the eye. In retinopathia centralis serosa, for example, a disease of the retina, increased stress leads to the formation of a scotoma.
Pathophysiologically, the whole thing is explained by an increase in hormones such as cortisol and adrenaline as well as blood pressure during stress. This causes cracks to appear in the choroid. Through these cracks, fluid gets under the retina and consequently lifts it or even loosens it completely.
People who show a low level of stress resistance or who are exposed to extremely stressful professional or private situations are particularly at risk.

Learn more about the Consequences of stress.

glaucoma

In glaucoma or glaucoma, increased intraocular pressure leads to destruction of the optic nerve and the retina. As a result, a scotoma develops.
The pressure is regulated by the aqueous humor, which enters the anterior chamber from the rear and flows off from there. If this drainage path is disturbed, the picture of glaucoma emerges.
Medically, one differentiates between primary and secondary glaucomas. Primary glaucomas arise spontaneously, while secondary glaucomas are the result of other diseases. Primary open-angle glaucoma is the most common form of glaucoma, accounting for around 90 percent of all glaucomatous diseases.
Characteristic of this disease is that the scotoma increases over the years. In addition, it is often discovered late because it appears in the external field of vision at the beginning and is compensated for by the other eye.

Find out about the Symptoms of Glaucoma.

stroke

During a stroke, insufficient perfusion of the brain with oxygen leads to the death of brain tissue. Depending on the location of the stroke, parts of the visual center can also be affected by this tissue death. The first signs of a stroke are often double vision and visual field deficits, but also hemiplegia of the body and speech disorders.

Read our articles about this:

• Impaired vision after a stroke
• Signs of a stroke

There are two types of stroke. The ischemic stroke (anemic) and the hemorrhagic stroke (blood rich). Approx. 90% of the cases can be assigned to ischemic stroke. A vascular plug (thrombus) clogs the supplying vessels, which leads to a reduced perfusion of the brain. These thrombi are most commonly caused by arteriosclerosis. However, they can also be triggered by an embolism. This means that the thrombus originates in a different location (e.g. the heart) and is flushed into the brain via the bloodstream, where it "gets stuck". The remaining 10% is hemorrhagic stroke. The cause here is a bleeding within the brain. Not only does this increase intracranial pressure, as more and more blood flows into the skull instead of the vascular system. The supply area is also no longer adequately supplied with oxygen-rich blood. The distinction between these two forms is extremely important because they are treated completely differently.

Learn more about the Causes of a stroke.

migraine

A migraine causes the so-called flicker scotoma. Patients perceive this as bright, flickering or kaleidoscopic rotating light in a part of the field of vision that is mostly outside the center. It initially expands, but does not cover the entire field of vision. The occurrence happens suddenly.

Medically, migraines without aura can be differentiated from those with aura.
With scotoma as a result of migraines without aura, there are concomitantly stronger, pulsating, one-sided headaches, vomiting and nausea as well as additional sensitivity to noise and light.
If the scotoma occurs due to a migraine with aura, other neurological symptoms appear in addition to the scotoma. These additional complaints are the so-called "aura" and herald the headache that will soon set in. They include speech disorders, changes in feeling such as tingling in arms and legs, fortifications (perception of additional jagged lines) and balance disorders.

Do you suffer from migraines? Find out about the symptoms of a Migraine attack and what you can do about it.

How is visual field loss presented?

A visual field loss describes the weakening or even the loss of part of the visual field. Visual perception is limited or suspended in this area. Possible forms of representation can be:

• Flashes of light,
• small, dancing dots (so-called floaters),
• Color changes,
• dark spots or else
• total blindness.

What forms are there?

You can first differentiate a scotoma according to the degree of severity. A complete loss of sensitivity, i.e. blindness, is referred to as an absolute scotoma, while a partial loss of sensitivity is referred to as a relative scotoma.
In addition, one can differentiate scotomas according to their respective failure pattern. These special forms include:

• Paracentral scotoma
• Central scotoma
• Seidel scotoma
• Bjerrum's scotoma
• Centrozecalskotom
• Fixation point scotoma
• Ciliated scotoma

What is a central scotoma?

The central scotoma is a form of visual field loss that affects the central visual field (in the area of ​​the fovea centralis) without affecting the blind spot. If the latter is the case, one speaks of a centrozecalskotom.
A central scotoma occurs as part of a macular lesion or optic nerve damage. E.g. with an optic nerve damage in the form of papillitis or retrobulbar neuritis and can thus be an early sign of multiple sclerosis.

Paracentral scotoma

The paracentral scotoma is an isolated visual field defect (scotoma) in the Bjerrum area of ​​the visual field (section of the visual field that - from the blind spot - arches around the macula between 5 ° and 20 ° from the fixation point below and above). A paracentral scotoma with inclusion of the blind spot is called a Seidel scotoma.

Diagnosis of the scotoma

If the visual field defects occur for the first time, it is strongly advisable to see an ophthalmologist as soon as possible. The longer the symptoms persist, the worse the prognosis.
In the anamnesis, the patient explains his symptoms to the doctor and is asked about relevant comorbidities such as diabetes, high blood pressure or glaucoma.
The visual acuity is then checked and it is checked whether the patient has a distorted perception of his surroundings. With the help of a slit lamp (special microscope), the structures of the eye are examined, from the front part with cornea and lens to the fundus and retina. During the ophthalmoscope, the point of sharpest vision, the fovea centralis, located in the center of the macula (yellow spot) is assessed.

Concomitant symptoms

The accompanying symptoms depend on the cause of the scotoma and cannot be named generally.
If the scotoma is the expression of a stroke, double vision, hemiplegia of the body and speech disorders can also occur.
If glaucoma causes the scotoma, the patient will have severe to no symptoms depending on the type of glaucoma. These include sudden, dull or pressing, severe pain in the diseased eye, the half of the face on the same side, the teeth or even the stomach. In addition, dizziness, nausea, malaise and vomiting can occur. Therefore, at first glance, glaucoma can easily be mistaken for a migraine attack. Typically, the heart of glaucoma patients beats too slowly (bradycardium) or irregularly (arrhythmically).
Scotomas that develop as a result of stress can be accompanied by a variety of symptoms. Classical here are an increase in heart rate and blood pressure, muscle tension with the resulting headache and back pain, difficulty falling asleep or staying asleep, difficulty concentrating or a weakened immune system and thus an increased susceptibility to illness.

Therapy of the scotoma

The treatment is as varied as the various causes of the scotoma. In the case of a scotoma, you cannot treat symptomatically, you have to eliminate the causal symptoms.

The aim of glaucoma therapy is to use drugs to lower the increased intraocular pressure. This may be followed by an operation or laser treatment. A small piece of the iris is removed. This creates an artificial drain between the anterior and posterior chambers of the eye, through which the aqueous humor can drain.

Read all about the process, the risks and the follow-up treatment OP of glaucoma.

In the case of ischemic stroke, lysis therapy is started immediately to dissolve the thrombus that is clogging the vessel. In the case of a hemorrhagic stroke, the patient is raised in the upper body to promote blood flow from the head, mannitol is given to lower the increased intracranial pressure, and if it does not improve, a neurosurgical procedure is carried out.

Find out more in the following articles:

• Actions in the event of a stroke
• Stroke therapy

In order to treat stress, as a trigger of scotoma, the patient must find out what is causing the stress and try to avoid or at least reduce contact with this source. Psychological help can also be supportive and useful.

Learn how to reduce stress can.

In the treatment of migraines one uses medication against nausea and pain. The triptans class of active ingredients has proven to be particularly effective in recent years. These are not painkillers in the classic sense, but specifically effective in migraine attacks.

Find out about the Therapy for migraines.

Duration

The duration of the scotoma depends on the cause of the development of the scotoma, how quickly it is found and then treated. As long as the associated brain area is insufficiently supplied with oxygen, there is increased intracranial pressure or there is a disease of the retina or the optic nerve, there will be no improvement. However, an exact time cannot be given.
The occurrence of a shimmering scotoma as part of a migraine, however, is limited in time. Usually the duration is limited to approx. 20 to 30 minutes.

Prognosis of the scotoma

The prognosis of the scotoma also depends on the underlying disease and can vary from completely reversible courses to complete blindness.
If a scotoma develops as a result of a head injury or a stroke, the chances of complete vision restoration after a timely operation are good.
The occurrence of a shimmering scotoma as part of a migraine is also reversible and even temporary.
However, if the underlying cause is a disease of the retina, the visual field loss remains irreparable forever. In this case, the only bright spot for patients is that the progression of the visual impairment is stopped or at least slowed down by therapy for the underlying disease.

What is the difference between a blind spot and a scotoma?

The blind spot is a physiological scotoma that is completely normal and occurs in everyone. In the place of the blind spot, the optic nerve enters the eyeball. There are no photoreceptors there, which causes a bilateral visual field loss approx. 15 degrees temporal to the visual field center. As a result, objects that are at a certain angle to the blind spot are not seen. However, this effect is compensated by the other eye, so that we do not even perceive the blind spot as such.
In contrast, the scotoma always has a disease value. The causes for its occurrence can be varied and dangerous to different degrees. If a visual field loss occurs, this should be clarified and treated as soon as possible.