Posterior vitreous separation, or posterior vitreous detachment, is a common age related degeneration of the vitreous – the jelly in the back of the eye - becomes detached from the retina. This gives rise to the visualisations of floaters. As the vitreous detaches it pulls on the retina causing the individual to experience flashing lights.

It should not be confused with the more serious condition, retinal detachment. There are several warning signs for retinal detachment, and you should get an urgent re-examination if you experience any of the following:A sudden increase in the number of floaters in your visionDecrease in visual fieldVeil coming across vision