Floaters are caused by opacities in the vitreous casting a shadow on the retina. The majority results from vitreous degeneration and is more common amongst the  myopic and elderly population. The condition is benign in most cases but they may be a potentially serious retinal problem.

Presentation:

They may be a gradual increase in floaters in both eyes or

Sudden onset of floaters in one eye with or without flashing light (photopsia, caused by pulling of the retina by the vitreous)

• The visual acuity is normal unless there is an associated vitreous haemorrhage or retinal detachment.
• The vitreous may be visible with direct ophthalmoscope, but better seen on the slit-lamp.

       The history is crucial in deciding on the urgency of referral:

• patient with gradual on-set floaters in both eyes are unlikely to have serious retinal problems, however, refer the patient within one week
• patient with sudden onset floaters with photopsia may have impending retinal tear. Referred within 24 hours.

Figure 1.  This patient presented with a sudden onset of floater in her right eye.  The picture shows the presence of Weiss's ring in the vitreous cavity.  The ring  is caused by vitreous detachment from the optic disc edge.  Note the ring shaped opacity corresponding to the size of the optic disc. The retina view is blurred because the camera was focused on the vitreous. See also retinal detachment.

Figure 2. A diagramatic representation of posterior vitreous detachment. The vitreous  gel is apposed to the retina and if detachment can sometimes give rise to retinal  tear or hole. If the retinal vessels were pulled, vitreous haemorrhage can result.

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