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Ask Dr. K: Most eye ‘floaters’ are a harmless nuisance

THURSDAY, NOV. 7, 2013

DEAR DOCTOR K: At 65, I have begun to notice tiny threadlike shapes in my vision. My doctor calls them “floaters.” Should I be concerned?

DEAR READER: “Floaters” describes the dots, threads or cobwebs that we notice drifting across our line of vision as we get older. You’re more likely to notice floaters when you are looking at a page of a book, a computer screen or a solid, light background. Floaters move as your eye moves and dart away when you try to look at them.

To understand floaters, here’s a quick refresher on how your eyes are built. The light that enters your eyes through the pupil passes through a crystalline lens inside the eye. The lens focuses the light on the back of your eye: the retina. It’s similar to the lens on a camera focusing light on the film (or, these days, on the digital sensor).

The retina is the light-sensitive area where the whole image is registered before it is sent to the brain. The brain then interprets the image.

Between the lens and the retina is a fluid called the vitreous. Floaters form in the vitreous. They are tiny clusters of cells or flecks of protein. When light coming into your eyes hits one of these little floaters, it casts a shadow on the retina.

Floaters can be removed with surgery. Eye surgery these days is much more effective and safe than it was decades ago, but there is always a risk with surgery. One of my patients had surgery and has been forever grateful.

Most of my patients just learn to live with floaters. If they become a nuisance, moving your eye up and down or left and right may shift the floaters and provide temporary relief.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.

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