Floaters are small specks, strands or clumps or aggregates of cells that move through a person’s field of vision. Flashes, as the name suggests, are sudden flashes of light or "lightning streaks." Both are caused by changes related to aging that take place in the vitreous. Flashing lights may be associated with high nearsightedness and could indicate a serious retinal problem. 

What causes floaters and flashes?

The vitreous is the gel-like fluid that fills the eyeball. Around middle age, this gel may begin to thicken, and as it does, small clumps or strands of cells may form. These clumps get in the way of the light entering your eye and cause you to see floaters. Some will fade after a time, but other floaters remain for years.

Flashes are caused when the shrinking vitreous pulls at areas of the retina where it is tightly adhered. This pulling or tugging pressure on the retina produces a sensation of light, similar to when you press the side of your eye with your finger. This could indicate a retinal tear or detachment, which is a sight threatening condition.

What are the symptoms and signs of floaters and flashes?

If a spot or shadowy shape passes in front of your field of vision or to the side, you are seeing a floater. Because they are inside your eye, they move with your eyes when you try to see them. Floaters may appear as different shapes, such as specks, clouds, dots, circles, lines, or cobwebs. You can often see them when looking at a plain background, like a blank wall or blue sky.

You may also see flashes of light. These flashes occur more often in older people, and usually are caused by mechanical stimulation of photoreceptors when the gel-like vitreous occasionally tugs on the light-sensitive retina. They may be a warning sign of a detached retina. Flashes also occur after a blow to the head, often called "seeing stars."

Some people experience flashes of light that appear as jagged lines or "heat waves" in both eyes at once, lasting 10 to 20 minutes. These types of flashes are usually caused by a spasm of blood vessels in the brain, which is called migraine.

What is the treatment that is available for floaters and flashes?

In general, floaters do not require any treatment. However, all people with new onset of floaters or flashes, or a sudden increase in existing flashes or floaters, should be checked for torn retina by an ophthalmologist. This requires an examination with dilated pupils using an instrument called an indirect ophthalmoscope. This examination requires a bright light and gentle pressure on the eyelid, but is not painful. The reason this is important is that if caught early, torn retina can be easily repaired in the office with a laser. If retinal detachment is allowed to develop, surgery becomes necessary.

Since most floaters will diminish with time, treatment for the floaters themselves is not needed. For severe cases where a large floater obstructs vision, a form of laser surgery has recently become available at Shekar Nethralaya. Vitrectomy surgery, where the vitreous is removed and replaced with a clear fluid, is available for extensive and dense floaters which obstruct vision, but is a major eye operation and is not appropriate for floaters which are simply annoying, but do not obstruct vision