Vitreous floater

Floaters are a very common symptom that becomes more frequent with age.

This term describes the perception of a moving shadow of varying density in the visual field, sometimes described as a floating fly, cobweb or strand of hair.

This perception is caused by less transparent material appearing in the vitreous cavity. The vitreous fills the back part of the eye and should ideally be optically clear. When it is not, light entering the eye casts shadows that the retina detects. For this reason, floaters are more easily and frequently noticed in bright conditions.

The main cause of reduced vitreous transparency is ageing. Symptoms may develop earlier in short-sighted patients and after injury or surgery.

Less often, floaters can indicate inflammation or bleeding inside the eye.

Whenever floaters are new or worsen, the retina should be examined carefully because retinal tears may be present and need treatment to prevent progression to retinal detachment.

This information does not replace an individual medical assessment. Follow the advice of the team looking after you.

Dr. Nuno Lopes · Patient information
Editorial presentation updated on 27 October 2026. Your team's individual instructions take priority.