Many people have floaters which are little black opacities in vision, often seen against a brightly lit white wall or sky.
The opacities are proteins clumps formed from the jelly in the middle of the eye called the vitreous humour. As we get older the jelly becomes more watery and more floaters become visible.
Flashing lights can often be associated with migraine. These ocular disturbances should not last more than 20 minutes, often are followed by a headache (although not always) and will usually affect both eyes to some extent.
Indication of Retinal Damage - IMPORTANT
Flashes and floaters together can be a sign of a retinal tear or retinal detachment and should always be taken seriously. Any sudden appearance of new floaters should be investigated by an optometrist urgently.
With a retinal tear, the floaters and flashing lights will be in one eye (unless the person is unfortunate enough to have simultaneous retinal tears in each eye, which would be very rare).
A retinal detachment often starts with a tear in the retina, fluid then gets underneath the tear and pulls off the retina from the layer below. As the retina detaches the vision will disappear from that region, so the next symptom is called ‘Falling Curtain’, as the sight is lost as the retinal detaches, and as this happens the person’s vision fails.
The 4 F's of retinal detachment are: Flashes, Floaters, Falling curtain, Failing vision.
If you have any new symptoms it is important to get an optometrist appointment the same day to investigate the cause. Retinas can be re-attached, but the results are better when treated in an early stage.
Posterior Vitrous Detachment
A more common condition where flashes and floaters can be present is Posterior Vitrous Detachment.
This usually occurs between the ages of 60 -75 years and occurs when the vitreous jelly detaches from the retina.
It causes a large floater and often a 'lightening strike' flashes in the peripheral vision, but it does not cause a loss of vision.
It is advised that all cases of posterior vitreous detachment are seen by an optometrist to rule out any retinal tears or detachment which can occur in about 2-5% of cases.