Floaters, vitreous opacity & Mouches Volantes in the eye: Symptoms, Causes & Treatment

They look like dancing dots, thread-like streaks or tiny gnats floating through the field of vision – and they cannot be fixed or simply blinked away: floaters, also known as mouches volantes, are a common phenomenon caused by changes in the vitreous body of the eye.

But what exactly is behind them? Are they harmless or a warning sign of a serious eye disease such as retinal detachment? And what should you do if vitreous opacities impair your everyday vision?

In this blog you will learn:

• What mouches volantes actually are and how they develop
• When they are particularly noticeable
• Which symptoms should be taken seriously
• What treatment options are available – from laser to vitrectomy
• And when a visit to the ophthalmologist makes sense

Floaters in the eye – what are the flying mosquitoes?

Almost everyone sees them at some point: small, flying shadows, dots or threads that dance through the field of vision like tiny gnats. In medical terms, they are known as “mouches volantes” or “floaters” – harmless but sometimes disturbing phenomena in the vitreous body of the eye. They are particularly visible against a light background, such as a white wall or when looking up at the sky.

Even if they are annoying: In most cases, floaters are not dangerous, but a normal part of the ageing process of the eye.

Mouches Volantes: When streaks and shadows disturb vision

Mouches volantes (French for “flying flies”) look like streaks, threads or clumps that seem to move weightlessly in the field of vision. These visual effects do not occur on the retina, but in the vitreous humor itself – the gel-like interior of the eyeball that lies between the lens and the retina.

Typical complaints:

• “Black spots” or “soot rain” in the field of vision
• Moving shadows when rolling your eyes
• Flying mosquitoes that elude the eye
• Increased occurrence in bright environments or during long screen time

How do vitreous opacities develop?

With increasing age, the vitreous body loses its homogeneous, clear structure. The collagen fibres and other components of the gel-like substance clump together or form microparticles – the result: vitreous opacities that scatter light and thus cause the typical floater symptoms.

In addition to natural ageing, short-sightedness, eye injuries, inflammation or metabolic diseases (e.g. high blood pressure) also play a role in their development. In rare cases, a vitreous detachment can even lead to a retinal tear or retinal detachment – which is why medical advice should be sought immediately if numerous floaters suddenly appear.

Are floaters dangerous or just annoying?

For most people, floaters are primarily one thing: unusual and irritating. As a rule, vitreous opacities are harmless and do not require treatment. Especially with age-related changes in the vitreous body, the appearance of mouches volantes is a typical symptom – the spots, streaks or flying mosquitoes are disturbing, but have no influence on the retina or actual vision.

In many cases, the brain gets used to the visual disturbances over time – they become less noticeable or are even completely ignored.

Nevertheless, not every vitreous change is harmless. In rare cases, a sudden increase in floaters, combined with other symptoms, can be a serious warning sign.

Warning signs of retinal detachment:

Suddenly appearing floaters that multiply rapidly or are accompanied by other visual disturbances should definitely be clarified by a doctor. Particularly critical are:

• Flashes of light or “photopsia”
• A soot rain of many small black dots
• A shadow or “curtain” in the field of vision
• Severe deterioration of vision in a short time

These symptoms can indicate retinal detachment or a retinal tear – both emergencies that require immediate ophthalmological clarification. Without rapid treatment, permanent vision loss can occur in such cases.

When you see Mouches Volantes particularly strongly

Floaters – i.e. Mouches Volantes – appear particularly clearly when the eye looks at a homogeneous, bright surface. Classic situations in which vitreous opacities are perceived as particularly disturbing are:

• When looking at a white wall or bright sky
• When reading on a bright screen
• In light-filled rooms with strong sunlight
• When rolling your eyes or making rapid eye movements

The reason: In such situations, light hits the clumps in the vitreous body unhindered, which are then perceived as spotty shadows or streaks on the retina. In dark environments or during focused close-up work, however, the opacities are often barely noticeable.

Treatment options for disturbing vitreous opacities

In most cases, floaters are unpleasant, but do not require treatment. Many patients get used to vitreous opacities over time, and the brain learns to filter out visual disturbances. Nevertheless, there are situations in which floaters so severely impair vision that treatment becomes sensible or even necessary.

Two medical options are available for patients with severe distress:

• Vitreolysis with laser – a minimally invasive procedure
• Surgical vitrectomy – a more invasive procedure for removing the vitreous body

Vitreolysis with laser – when this treatment makes sense

Vitreolysis is a painless laser treatment in which vitreous opacities are specifically destroyed or reduced in size so that they are no longer perceived as disturbing. A YAG laser is directed through the pupil at the clumped collagen fibres. These are dissolved into smaller particles that can be better distributed or filtered out by the brain.

This method is particularly suitable for:

• Clearly defined floaters that are centrally located in the field of vision
• Single large opacities that are very disturbing
• Younger patients without additional eye diseases

The treatment is performed on an outpatient basis and usually under local anaesthesia using eye drops. It is relatively low-risk, but not suitable for all types of floaters – e.g. in the case of very diffuse opacities or proximity to the retina.

The decision for vitreolysis should always be made individually and after a thorough ophthalmological examination. It offers a gentle way to improve vision without having to resort to surgical intervention.