Private flashes, floaters and retinal detachment clinic in London, same-day eye.

The common, harmless kind

Small specks, threads or cobwebs drifting across your vision, most noticeable against a bright plain background such as the sky or a white wall, moving as your eye moves and drifting on when it stops. These are shadows cast by strands in the vitreous jelly. They are extremely common from middle age onwards, tend to become less noticeable over months as the brain filters them out, and need no treatment.

What changes the picture

• Sudden onset rather than gradual
• Many new floaters at once, sometimes described as soot, smoke or a swarm of flies
• Flashes — brief arcs or streaks of light, typically at the edge of vision and worse in the dark
• Any loss of visual field, however small, or a shadow that is not moving with your eye

Who is at higher risk

• Short-sightedness, particularly strong prescriptions — the commonest risk factor
• age over 50
• previous cataract surgery or other eye surgery
• a previous retinal tear or detachment, in either eye
• a family history of retinal detachment
• eye injury, and some inherited eye conditions

What examination involves

Drops are used to dilate the pupil, and the retina is examined in detail. Vision is blurred and light-sensitive for several hours afterwards, so you should not drive and should bring sunglasses. If a tear is found, laser or freezing treatment seals it, usually the same day and usually preventing detachment altogether.