Q: Sometimes I see small spots that drift across my field of vision. What are theyand are they anything to worry about?
A: What you describe sounds like floaters. The specks, squiggly lines, or other dark shadowy shapes you may see are minute clumps of debris in the vitreous humor (the gel inside the eyeball). They are most noticeable against a bright background, such as a white wall or blue sky, and may occur in one or both eyes.
Though young people can get them, floaters tend to increase with age due to normal changes in the vitreous humor, which starts to liquefy and shrink. People who are nearsighted, have diabetes, or have had an eye injury are also more susceptible to seeing these spots. You may be able to get floaters out of the way by moving your eye up and down, since this stirs up the gelor you may simply stop noticing them. Most floaters fade over time.
Floaters by themselves are nothing to worry about. But if you experience a sudden onset of many floaters, especially if they are accompanied by any change in vision, get immediate medical attention, since this could be an indication of a retinal tear or detachment, which can lead to permanent vision loss. You should also be checked right away if you experience spontaneous flashing lights in your visual field. Though in the great majority of cases the flashing is caused by the vitreous tugging harmlessly on the retina, it could also be the result of a retinal tear or detachment.
Source: Originally published in The University of California, Berkeley Wellness Letter (April 2011)