What causes floaters, or spots, in the eyes?

The innermost part of the eye is a large cavity filled with a jellylike fluid known as vitreous humour. Floaters are small flecks of protein, pigment or embryonic remnants (trapped in the cavity during the formation of the eye) that suspend in the vitreous humour.

The small specks appear to be in front of the eye because the semitransparent floaters are visible only when they fall within the line of sight. Most people might have specks trapped in the vitreous humour from time to time but not notice them. Eyes have a way of adjusting to imperfections, as any eyeglasses wearer with dirty lenses could tell you. Floaters are most likely to be noticed when one is looking at a plain background, such as a blackboard, a bare wall or the sky.

What should one do about floaters? An occasional spot is usually harmless, although sometimes floaters can be precursors of retinal damage. Most often, a home remedy will keep floaters from bothering you. The American Academy of Ophthalmology suggests:

'If a floater appears directly in your line of vision, the best thing to do is to move your eye around, which will cause the inside fluid to swirl and allow the floater to move put of the way. We are most accustomed to moving our eyes back and forth, but looking up and down will cause different current within the eye and may be more effective in getting the floaters out of the way'

Although you may be aware of their presence, it is often surprisingly difficult to isolate floaters in your line of vision. Because the floaters are actually within the eye, they move as your eyes move and seem to dart away whenever you try to focus on looking at them directly.