Some people may see flashes of light in front of one of their eyes, like small sparkles, lightening or fireworks. These tend to be in the extreme corners of your vision, come and go, and don’t obscure any part of your vision. The flashes don’t last for a defined length of time, and you may notice them more if you go from a light to a dark environment. They may continue for several months.
Flashes can occur when the gel in your eye becomes more liquid and “tugs” on the retina or may occur if you receive a hit in the eye. However, constant flashes may indicate a retinal tear or detachment and may be accompanied by a shadow at the edge of your vision. If this happens you should consult your optometrist straight away.
Flashes and migraines
Flashes are different to the shimmering or zig-zag lines that may be part of migraine. Migraine shimmers are a flickering of light, often only on one side of your vision with a sort of jagged pattern. This will often obscure a t least part of your vision (the left or right side). The shimmers usually go away after 10-20 minutes and may be followed by a headache, although some people may get migraine shimmers even if they do not have a headache afterwards.