When the eye is forming before birth, it is filled with blood vessels to allow the eye to develop. When fully formed, the inside of the back of the eye is filled with a clear jelly called vitreous and the blood vessels dissolve away. In later life, as part of the normal ageing process the vitreous shrinks. It then pulls away from the retina (which lines the back of the eye). Thicker parts of the vitreous may then be left floating inside the back of the eye. This casts a shadow, which you can see as a floater.
Floaters can be caused at other stages of life by some eye diseases, or by an eye operation such as cataract removal. Other kinds of spots before the eyes can also be associated with migraine and high blood pressure.
Are you imagining things?
Floaters are not imaginary. They can usually be seen by a doctor examining the back of your eye with an ophthalmoscope.
Since they are actually in the eye, floaters move with the eye and seem to disappear when you try to focus on them. They can best be seen by looking up at a plain white ceiling, or clear blue sky, when they can look like insects, spider web or veils.
Could it be serious?
Although floaters themselves are often harmless, they can be an indication that changes are occurring which could cause damage. Although the shrinking vitreous usually separates cleanly from the retina, it occasionally tears it.
If the retina is pulled away from the back of the eye so that it becomes loose, this can result in loss of vision. However, if diagnosed and treated early, this may be prevented.
Any other serious changes
If the vitreous is pulling on the retina it will stimulate the nerve cells, causing flashing lights, or lightning flashes which look like a flickering fluorescent tube. There may also be a loss of part or all of the vision in the affected eye. If you see new spots before your eyes, or suddenly experience flashing lights, or a partial loss of vision, this is a warning that your eyes may be at risk.
Ask your family doctor to refer you to an Ophthalmologist straight away, so that the condition can be diagnosed accurately and treated, if necessary, to protect your vision.
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