If you see specks or what appears to be debris, or perhaps pieces of lint floating in your vision, these are “floaters”. They are usually harmless. They would be seen most easily while looking at a plain background, like a white wall or clear sky.
Floaters are in reality clumps of gel-like cells inside the vitreous – the clear, jelly-like fluid that fills the inside of your eye. Floaters look like webs, specks, strands, and other shapes. What you are seeing are in fact the shadows of floaters cast on the retina, the light-sensitive inner lining of the back eye panel.
With a special eye light, your doctor will detect floaters in your eyes even if you don’t notice them yourself. If a shadowy shape or spot passes in your field of vision or near the side, you are seeing a floater. Because they are inside your eye and suspended within the gel-vitreous, they move with your eyes as you scan and try to see them.
Some floaters are present forever as part of the eye’s development. Others can grow over time.
In middle age, the gel-vitreous begins to liquefy and contracts. Some parts of the vitreous form clumps or strands inside the eye. The vitreous pulls away from the back eye-wall causing a posterior vitreous detachment (PVD). PVD is a common cause of floaters.
With nearsightedness
After cataract surgery
After laser surgery of the eye
During or after inflammation in the eye
As mentioned above, most spots and floaters are harmless and only annoy the visual field. Many fade away on their own to become insignificant. Some doctors may perform surgery to remove floaters, but this should be advised only in rare cases.
Flashes of light occur often in older people and are usually due to mechanical stimulation of photoreceptors when the gel-like vitreous “pulls” on the light-sensitive retina. They may be an early warning sign predicting a detached retina – a serious problem which could lead to blindness if not treated immediately.
Some experiences of light flashes appear as jagged lines or “wavy heat” in both eyes, lasting 10-20 minutes. These types of flashes are usually caused by a spasm of the blood vessels in the brain, also called a migraine. If a headache follows the flashes, these are known as migraine headaches. Jagged lines or “heat waves” however can and do occur without a headache. These light flashes are called an ophthalmic migraine -a migraine without a headache.
The sudden appearance of significant numbers of floaters, especially if accompanied by flashes of light or other vision disturbances, could indicate a retinal detachment or other serious problem in the eye. A study reported in the Journal of the American Medical Association in 2009 found that one in seven people with the sudden presence of eye floaters and flashes will have a retinal tear or detachment. If you suddenly see floaters, visit your eye doctor immediately.