Intended for healthcare professionals

Practice 10-Minute Consultation

Flashes, floaters, and a field defect

BMJ 2013; 347 doi: (Published 04 November 2013) Cite this as: BMJ 2013;347:f6496
  1. Ashraf A Khan, specialty registrar in ophthalmology1,
  2. Ross J Kelly, general practitioner with special interest in ophthalmology2,
  3. Zia I Carrim, consultant in ophthalmology3
  1. 1Princess Alexandra Eye Pavilion, Edinburgh, UK
  2. 2St Paul’s Medical Centre, Carlisle, UK
  3. 3St James’s University Hospital, Leeds LS9 7TF, UK
  1. Correspondence to: Z I Carrim zia.carrim{at}
  • Accepted 7 August 2013

A 65 year old woman presents to her general practitioner with a three day history of flashing lights in her right eye. She has also noticed a new floater in her temporal field of vision. She describes this as resembling a “fly” or “cobweb.” Reassuringly, she has not been aware of a shadow in her field of vision.

Flashes, also known as photopsia, and floaters are a common complaint in primary care. Most patients with this complaint will have a simple, innocuous collapse of the vitreous gel, called a posterior vitreous detachment (figure). However, some may have more serious pathology. A rapid, systematic, assessment can facilitate appropriate management.

Diagram of the eye showing normal anatomy, posterior vitreous detachment with floaters (small opacities), and retinal detachment caused by a tear

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  • Photopsia characteristics, duration, and laterality—Intermittent white flashes of light in the temporal visual field, akin to camera or lightning flashes, usually correspond to stimulation of the retina as the shrinking vitreous “tugs” on it. These photopsias can be triggered by eye movement. Coloured lights and zig-zag lines, occurring in the visual field of one or both eyes simultaneously and persisting for minutes or hours at a time, are more likely …

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