A scotoma refers to the weakening or even loss of part of the visual field. The visual perception is restricted or cancelled in this area. Several forms of scotoma can be distinguished, depending on the place of origin and the severity of the failure.
The cause can be in the area of the eye, the visual pathway or the center of vision. Visual field perimetry is used to confirm the diagnosis of the scotoma. Therapy and prognosis differ depending on the underlying disease. In any case, an ophthalmologist should be consulted immediately when such symptoms occur, because the earlier the diagnosis and the start of therapy, the better.
Causes of the scotoma
There are many different causes of scotoma, which can be in the area of the eye, the visual pathway or the center of vision. Possible causes are:
- Diseases of the retina (e.g. retinal detachment)
- Diseases of the visual tract or visual center in the brain (e.g.
intracranial masses)
- Optic nerve damage (e.g. in papillitis or retrobulbar neuritis)
- Chronic glaucoma (scotomas increasing over years)
- Migraine (causes temporary scotomas such as the ciliated scotoma, appear suddenly, but usually disappear completely within a relatively short time)
- Stress
- Stroke
Stress is known to have different effects on the body. Among other things, it can also affect the eye. For example, in retinopathy centralis serosa, a disease of the retina, increased stress leads to the formation of a scotoma.
Pathophysiologically, this is explained by an increase in hormones such as cortisol and adrenaline as well as blood pressure under stress. This causes the formation of cracks in the choroid. Through these cracks, fluid gets under the retina and consequently lifts it or even detaches it completely.
Persons who show a low stress resistance or who are exposed to extremely stressful professional or private situations are particularly at risk. 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 passes from the posterior to the anterior chamber of the eye and flows out of there. If this outflow path is disturbed, the image of glaucoma appears. Medically, primary glaucoma is distinguished from secondary glaucoma.
Primary glaucoma develops spontaneously, while secondary glaucoma is the result of other diseases. Primary open-angle glaucoma is the most common form of glaucoma with about 90 percent of all glaucomatous diseases. Characteristic for this disease is that the scotoma increases over years.
In addition, it is often discovered late because it initially appears in the outer visual field and is compensated by the other eye. In a stroke, a reduced 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 loss of visual field, but also hemiplegia of the body and speech disorders. A migraine causes the so-called ciliated scotoma. Patients perceive this as bright, flickering or kaleidoscope-like rotating light in a part of the visual field that is usually outside the center.
It initially expands, but does not cover the entire visual field. The occurrence is sudden. Medically, migraine without aura can be distinguished from migraine with aura.
Scotoma as a consequence of migraine without aura is accompanied by a worsening, pulsating, unilateral headache, vomiting and nausea as well as additional sensitivity to noise and light. If the scotoma occurs as a result of migraine with aura, further neurological symptoms appear in addition to the scotoma. These additional complaints, are the so-called “aura” and announce the headaches that will soon begin. They include speech disorders, sensory changes such as tingling in arms and legs, fortifications (perception of additional jagged lines) and balance disorders.
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