Skip to main content
Consultant Ophthalmologist, Cataract & Refractive Surgeon
BMedSci BM BS MRCS MRCSEd MRCOpth FRCOphth MMedLaw PgD Cataract & Refractive Surgery

Flashes and Floaters

Flashes and floaters are common symptoms, and in most cases represent no significant pathology, especially if they are long-standing. Possible causes include a posterior vitreous detachment, ocular migraine and vitreous haemorrhage.

Sometimes the posterior vitreous detachment causes a retinal hole to form, with the subsequent risk of retinal detachment.

  • Long-standing flashes and floaters – no need to refer.
  • Flashes and floaters of under six weeks' duration – refer soon via letter
  • Flashes and floaters with decreased vision – refer urgently.

Judge each case on its merits.

  • Certain risk factors should be taken into account, and these features will increase the suspicion of pathology:
    • Myopia, particularly if highly myopic – look at the thickness of the lenses in the patient's glasses
    • Younger age, i.e., under 55 years
    • Pseudophakia/aphakia (previous cataract extraction – pseudophakia means replacement lens placed, aphakia means no lens placed).
  • All patients should be warned about the symptoms of retinal detachment and advised to contact the hospital eye service urgently if they experience the following:
    • Sudden increase in floaters ('swarm of tadpoles').
    • Solid or grey curtain moving across peripheral field of vision.

Is there a retinal tear or hole?

  • The only way to know is for an ophthalmologist to examine the retina with specialised lenses and visualise every part.
  • Ideally, this should be done for every patient but resources are not available for such blanket screening.
  • Optometrists are skilled at fundoscopy and many use slit lamp biomiscroscopy to assess the retina. They are thus a good initial port of call for such patients.

Is this a posterior vitreous detachment (PVD)?

  • Probably. The key question is whether this has caused a retinal tear.
  • PVD is a normal ageing phenomenon – it may occur without symptoms or cause flashes and floaters.
  • The flashes are usually short–lived but floaters may persist.
  • Classically, patients describe a single spider's web or floater complex which 'wobbles' in and out of vision.
  • Often flashes persist, particularly at night or on eye movement.