Ophthalmology | Flickering, flashes, zigzag lines

Blurred vision can also be a warning sign - for cataracts or glaucoma, among other things. Photo: imago/Seeliger Great eye theater: fog, blinding light in the middle, plus many small points of light. Or colorful zigzag lines. Or blindness in the middle. Flashing or stationary bright lights, colorful dots, circles or geometric shapes. Or the blurry image becomes distorted and glows in color. Lightning, flickering, stars, sparks – everything seems possible. But these phenomena are not a drunken life or a film about New Year's Eve or an amusement park. They are signs of illness. Anyone who sees them may need urgent medical attention.

With such an acute experience, which usually subsides quickly, patients also come to the ophthalmologist. With a view to this year's congress of the German Ophthalmological Society (DOG) in Berlin this week, the organizers have pointed out the topic in advance. In order to recognize what lies behind the unusual lights or dark areas, a certain amount of systematics is required. Julia Biermann, who works both at the Bielefeld Clinic and in a practice in Münster, gave an overview of this. The ophthalmologist first distinguishes whether the phenomena are positive - i.e. something additional is seen - or negative, when less of the environment is seen.

Sudden, temporary blindness can be a sign of a stroke.

Another difference is whether both eyes are affected or just one. This cannot always be clarified retroactively because very few patients in the situation close one eye at a time to understand this. Unilateral vision problems point to causes in the parts of the eye that lie in front of the retina, i.e. in the vitreous body, or in the retina itself, in the optic nerve or in the choroid. If the phenomena are seen on both sides, then the causes lie behind the intersection of the optic nerves, at the base of the skull directly below the brain. The triggers can be varied: a drop in blood pressure due to getting up too quickly, fluctuations in blood sugar or side effects of medication; Pressing breathing air against a closed mouth and nose can also lead to a visual disturbance.

Another important criterion for distinguishing the phenomena is whether they are associated with headaches or not. This is the case with migraines, among other things. And here the visual effects are also very diverse. “Up to 26 different disorders have been described,” explains Biermann, “and they are always bilateral. But patients often perceive them as one-sided." What is typical of this visual "aura" in migraines is that the disorder builds up slowly within five minutes and lasts up to an hour, and is often - but not always - associated with the headache. Migraine aura with visual events is also the most common. According to Biermann, the corresponding perceptions move towards the periphery across the field of vision - and then disappear irreversibly. However, if it occurs again, either an ophthalmological or a neurological examination is recommended.

A most alarming sign of a stroke can be a blockage of the retinal arteries. The technical term is amaurosis fugax. This sudden, painless and quickly temporary blindness or visual impairment usually only affects one eye. The event can be a harbinger of an impending stroke and lasts a maximum of a minute. If diagnosed by doctors, patients should be referred to a neurological clinic or emergency room immediately - up to two weeks after such an event.

Other causes of vision problems include retinal detachments, increased intracranial pressure or a specific form of glaucoma. The latter is manifested by blurred vision and halos, i.e. colored and bright rings around light sources, and is associated with headaches, nausea and vomiting. Here, too, patients should go to the ophthalmologist or emergency eye service immediately. Small dots or shadowy shapes that move with your gaze are rather harmless - these are usually caused by age-related clouding of the vitreous body.

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