Flashes and floaters are visual phenomena associated with changes occurring to the back compartment of the eye. Floaters are small dark shapes that appear in your field of vision. Often times they look like squiggly lines, specks or cobwebs that move with eye movement. They are most apparent against light background colors or in well-lit areas. Flashing lights can be described as thunderbolts, a spark or an arc of light occurring in the periphery of vision.
Floaters occur when the vitreous, the jelly in the back of the eye, degenerates or shrinks. As the vitreous shrinks, strands form that cast a shadow upon the retina. While these strands look like they are in front of your eye, they are actually inside your eye. The vitreous tends to degenerate with age. This process is also accelerated in people who are very nearsighted or have incurred ocular trauma among many other causes. A complete breakdown of the vitreous and separation from its attachment to the retina can cause a posterior vitreous detachment. This appears as a large ring-like floater. Approximately 15% of posterior vitreous detachments are associated with an underlying retinal detachment.
Flashes occur when the vitreous is bouncing against or tugging on the retina. This mechanical action translates as a flash of light by the retina. Vitreous degeneration and retinal detachment can both trigger symptoms of flashing lights.
Since a retinal detachment is a serious vision-threatening consequence that can be associated with symptoms of flashing lights and floaters, an examination by an ophthalmologist is recommended.
While flashing lights and floaters become more common with age you should alert your ophthalmologist if you notice the following:
a large new floater or a shower of floaters
sudden onset of flashing lights
a loss of vision in the periphery
There is no treatment for floaters. Over time, these strands may settle at the bottom of the eye but never fully go away. In rare cases, some surgeons may perform a vitrectomy to remove the vitreous of the eye and replace it with a saline solution. This is rarely recommended.
If flashing lights are associated with normal aging, no treatments are available. If the symptoms of flashing lights or floaters are associated with an underlying retinal tear or detachment then further options are available. These include laser treatment or surgical repair of the retina.