"Eye floaters" are deposits or condensation in the vitreous jelly of the eye. People use the term eye floaters to describe seeing floating spots within their vision when they look around. Eye floaters may be present in only one eye or both eyes.
The structures in the front of the eye (the cornea and lens) focus rays of light onto the retina. Light focused onto the retina allows one to see. The light going to the retina passes through the vitreous humor, which is a jellylike material which occupies the back 2/3 of the eye. At birth and during childhood years, the vitreous gel is totally clear. Later in life, sometimes strands, deposits, or liquid pockets develop within the vitreous jelly. Each of these strands casts a small shadow onto the surface of the retina, and these shadows are perceived by the patient as eye floaters. As the eye moves from side to side or up and down, these strands, deposits, or pockets also shift in position within the eye, making the shadows also move and appear to float or undulate.
People describe eye floaters as spots, straight and curved lines, strings, or "O" or "C" shaped blobs. Some people see a single floater while others may think they see hundreds. The lines may be thick or thin, and they sometimes appear to be branched. To most people, they appear grey or dark in color. The density of different eye floaters will vary within an individual eye. Eye floaters may be more noticeable under certain lighting conditions and be more apparent when looking at a bright sky.
Like fingerprints, no two people have exactly identical patterns of eye floaters. If a person has eye floaters in both eyes, the pattern of the eye floaters in each eye will be different. In any eye that has eye floaters, that pattern of eye floaters may also change over time.
Eye floaters always appear darker than the background and cannot be seen in darkness or with the eyes closed. This is unlike flashes, which often are seen in the dark and with your eyes closed.
Any eye condition in which the clarity of the vitreous humor is altered can produce the symptom of eye floaters. As one gets older, changes normally begin within the vitreous humor. The vitreous jelly naturally undergoes some liquefaction, resulting in small pockets of more liquid vitreous lying within the firmer gel. This is called vitreous syneresis. The boundary between each liquid pocket and the gel may be noticeable to the person as one or more eye floaters. In addition, it normal for the collagen fibers that are within the vitreous to become thickened and denser with age, resulting in eye floaters. Any person who is over 50 will have these changes within their eyes. However, the degree of eye floaters produced by these typical changes will vary from person to person.
As the vitreous normally ages, the gelatinous structure also begins to shrink within the space that it occupies. This shrinkage often leads to the back surface of the vitreous moving forward within that space. The vitreous is normally attached to the edges of the optic nerve. As the vitreous shrinks, this attachment to the optic nerve may release, and this former attachment now floats within the eye, causing one or more eye floaters which can sometimes seem very large and circular in shape. In addition, the back surface of the vitreous, now floating within the eye, will also cast shadows onto the retina, producing eye floaters. This shrinkage and pulling away of the back of the vitreous is called a posterior vitreous detachment (PVD) or posterior vitreous separation. It is not the same as a retinal detachment. About 50% of people aged 65 will have a PVD in one or both eyes. A person developing a PVD in one eye is likely to develop a PVD in the other eye within the following 18 months.
In addition to vitreous syneresis and posterior vitreous detachments, both of which are normal occurrences that cause eye floaters, there are a large number of abnormalities in the eyes that may also cause the symptoms of eye floaters. Any cellular material within the vitreous may cause eye floaters. Red blood cells as a result of hemorrhage and white blood cells as a result of inflammation are common types of cellular material causing eye floaters. Hemorrhage into the vitreous may be a result of injury, diabetic retinopathy, a retinal tear through a blood vessel, or eye surgery. Inflammation in the vitreous may be caused by uveitis, injury, infection, or eye surgery.
Eye floaters are extremely common in adults and are a leading symptom that causes people to see an ophthalmologist. Almost everyone has eye floaters by age 70, although some people are much more aware of them than others. It is unusual for children under 16 years of age to notice eye floaters.
Eye floaters are associated with the retinopathy of diabetes, retinal tears, retinal detachment, and large degrees of nearsightedness. They occur more commonly in people who have had injury to the eyes, surgery to remove cataracts, or YAG laser surgery after cataract surgery. Tuberculosis, sarcoidosis, syphilis, and toxoplasmosis of the eye are other diseases that are associated with eye floaters. An unusual ocular condition called asteroid hyalosis is also a cause of eye floaters. Primary or secondary tumors in the eye, including lymphoma and leukemia, are associated with eye floaters, but these are extremely rare.
Being nearsighted (myopic) is a risk factor for eye floaters occurring earlier in life. The process of vitreous syneresis is accelerated in eyes that are highly myopic, and posterior vitreous detachments occur at a younger age in people who are significantly nearsighted. Diabetes is a risk factor for the development of eye floaters that arise due to diabetic retinopathy. Eye injury is an additional risk factor.
Eye floaters can be annoying, but by themselves they are not dangerous. The majority of eye floaters are caused by normal aging changes within the eye. However, a person developing symptoms of eye floaters should be checked by an ophthalmologist to make certain that there is no associated eye abnormality which requires treatment. A sudden onset of many eye floaters or the onset of eye floaters associated with flashing lights could signify a retinal tear that requires treatment to prevent retinal detachment. A curtain or cloud in the vision or a loss of side vision could be a symptom of associated retinal detachment.
When you go to your ophthalmologist with the symptom of eye floaters, he or she will first ask you questions about them. The ophthalmologist will check your vision, look at the front of your eyes with a slit lamp, and then place drops in the eyes to dilate the pupils. After the pupils are dilated, the retina and vitreous will be examined with bright lights from an ophthalmoscope. The ophthalmologist will be able to see the eye floaters themselves and will be able to tell you whether there are any associated abnormalities which require further tests or treatments.
Most eye floaters decrease in size and darkness with time. Some of this is due to actual absorption of the floater through the natural processes within the eye. Eye floaters may also shift in position within the eye, resulting in less of a shadow effect. In addition, the nerves within the brain adapt to and often becomes used to the presence of eye floaters, ignoring them in a manner similar to your only noticing the feeling of shoes on your feet when you think about it. Eye floaters eventually tend to become less bothersome.
There are no safe and proven methods to get rid of the symptoms of eye floaters caused by vitreous syneresis or posterior vitreous detachment. Most will fade over time and become less annoying or noticeable. Learning relaxation techniques may hasten the adaptation to persistent eye floaters.
Although certain herbs, vitamins, and iodine-containing products have been touted as effective in decreasing eye floaters, none of these have been proven effective in clinical trials. In the unusual cases where the eye floaters are due to white blood cells in the vitreous from inflammation or infection, appropriate anti-inflammatory drugs or antibiotics will reduce the number of white blood cells. There are no oral or eye drop medications of value for the reduction of the common type of eye floaters.
Breaking up of eye floaters by the use of a YAG laser has been advocated by some, but there is no evidence that this is effective. The use of a laser also poses significant risks to the vision in what is otherwise a healthy eye. The vitreous itself can also be surgically removed by a procedure called vitrectomy. This involves multiple incisions into the eye and is reserved for situations in which there is a large amount of non-clearing blood or inflammatory debris within the eye. Surgery of either type should not be performed in patients with the common type of eye floaters due to vitreous syneresis or posterior vitreous detachment.
