The symptom is familiar to many people: Small, dark “floaters” hover in the field of vision – like annoying mosquitoes that cannot be chased away. This phenomenon has many names: “mouches volantes”, “floaters” or “flying mosquitoes”. The cause is small opacities in the vitreous body, which are usually completely harmless, but which you should still take as an opportunity to see your ophthalmologist.


The vitreous body is gel-like and fills the inner part of the eyeball in the posterior chamber of the eye. It is located between the lens of the eye and the retina. The vitreous consists of 98% water. In young people, hyaluronic acid and fine connective tissue fibers are evenly distributed and ensure the transparency of the vitreous body. It is surrounded by a fine membrane adjacent to the lens in front and the retina at the back. This membrane adheres more firmly in the area of the center of the retina, the optic nerve and the outermost retinal periphery.

In the course of life, the vitreous body liquefies. This is a completely natural aging process. The originally invisible protein components and fibers clump together to form light-tight structures, the “floaters” or “flying mosquitoes” already mentioned (from the French “mouches volantes”). Especially against a light background, for example when reading, they are noticeable to those affected. The liquefaction also means that the vitreous body shrinks with age and the vitreous limiting membrane detaches from its base. This is also a normal process that affects most elderly people.

If your ophthalmologist has found floaters no further treatment is usually required. The opacities can be annoying, but they are harmless and are usually no longer perceived as annoying over time.

Operation of the vitreous body

In rare cases vitreous opacities are so severe that the ability to read or recognize faces is severely restricted or patients are even hindered in doing their job. Only then surgery can be considered. During the operation the vitreous body in which the most optically disturbing floating parts are located is surgically removed (vitrectomy). However, this microsurgical procedure should only be considered when vision is clearly affected, as the risks often outweigh the benefits.

Shrinking and detachment of the vitreous body from the retina can also be accompanied by other symptoms like flashing lights, a sudden increase of floaters or a black curtain appearing in the visual field. In this case, please contact your ophthalmologist or an eye emergency department immediately. An examination of the retina and posterior eye segment can determine whether there is a retinal tear, retinal detachment or hemorrhage and the appropriate therapy can be initiated. However, these symptoms occur less frequently compared to floaters.

Patients’ reports are very similar: First you see flight flashes, suddenly more floaters and then a curtain-like shadow over your field of vision. These are typical signs of a retinal detachment, in which the light-sensitive layer with the nerve cells detaches from the underlying pigment epithelium and can therefore no longer transmit a visual impression.

Retinal detachment (ablatio retinae)

Retinal detachment (ablatio retinae) is a very serious condition that must be treated immediately by an eye surgeon. Without treatment, the vision in the affected eye will be irreversibly damaged. Under certain circumstances, the eye can even go blind.