Retinal detachments often develop in eyes with retinas weakened by a hole or tear. This allows fluid to seep underneath, weakening the attachment so that the retina becomes detached - similar to wallpaper peeling off a damp wall. When detached, the retina cannot compose a clear picture and vision becomes blurred and dim.

If found early, it may only be necessary to have laser or freezing treatment however an operation will often be needed to repair a hole or put the retina back in place.

As the vitreous pulls free from the retina, it is often accompanied by light flashes or floaters. Floaters are caused by tiny bits of vitreous gel or cells that cast shadows on the retina. Flashes occur when the vitreous tugs on the sensitive retina tissue. There are other more serious causes of flashes and floaters, however. Retinal tears, retinal detachment, infection, inflammation, haemorrhage, or an injury such as a blow to the head may also cause floaters and flashes.

Signs include black spots or "spider webs" that seem to float in the vision in a cluster or alone, spots that move or remain suspended in one place, flickering or flashing lights that are most prominent when looking at a bright background like a clear, blue sky.

Surgical removal of the vitreous (vitrectomy) may be considered if the vision is significantly affected though this treatment is rare as most floaters typically become less bothersome over a period of weeks to months as they settle below the line of sight.