It may be the eye floaters which is mostly occur between ages 50 and 75, especially in people who are very nearsighted or have had cataract surgery. Once you develop eye floaters they usually do not go away, though they tend to improve over time.
Most eye floaters are caused by small flecks of a protein called collagen. The vitreous and its millions of fine collagen fibers shrink and become shred-like. Shreds can accumulate in the vitreous. This change causes the symptoms of eye floaters.
Also, eye floaters may be associated with the visual aura of migraine headaches, foreign bodies in eyes or other eye disorders. Check with your doctor for proper diagnosis.
Benign eye floaters almost never require medical treatment. You can move them away from your field of vision by moving your eyes. This maneuver shifts the fluid in your eyes. Looking up and down is usually more effective than looking from side to side.