Many people notice odd shapes that drift around when they move their eyes. In most cases, these "floaters" are gray or black and resemble spots, thread-like strings, cobwebs, or wavy lines. The floaters quickly dart away when one attempts to focus on them. Many conditions and factors lead to eye floaters, but very few are medical emergencies. Though treatments exist, they are not always necessary.
Occasionally, flashes or streaks of light may appear alongside floaters. Some people describe them as being similar to the stars that can appear after a head injury. The flashes may show up across several weeks, though they can occasionally last for several months. Though flashers and floaters are technically distinct symptoms, they typically result from similar conditions. Additionally, because they often appear together, the flashes can eclipse the floaters.
One of the primary causes of eye floaters and flashes is age. The vitreous is the gel-like substance that fills the eyes. Normally, this liquid helps the eyes maintain their round shape and is mostly transparent. As the body ages, the vitreous begins to shrink. As it shrinks, it becomes more stringy, and these strings can cast shadows on the eyes, causing floaters. Within the vitreous are millions of fine fibers that attach to the retina. When the vitreous shrinks, the fibers pull on the retina and often detach, which can cause an increase in the number of floaters that a person sees.
Uveitis is a general term that describes many inflammatory conditions that affect the middle layer of tissue in the eyewall , the uvea. A number of these are infections of some type, though harmful toxins, autoimmune issues, and physical trauma can also cause problems. The various forms of uveitis have numerous symptoms, and floaters are extremely common. Usually, floaters appear when the disease causes the release of inflammatory cells into the vitreous.
Eye damage can also prompt the development of floaters. Most trauma damages the vitreous, which can lead to detachment, bleeding, or inflammation. Occasionally, eye floaters appear as a result of a serious injury. Frequent blows to the head or eye area can cause the retina to detach or tear. Individuals who participate in combat sports and often experience trauma to the head or eye area are particularly prone to these injuries.
Certain medical procedures require an injection straight into the vitreous of the eyes. Sometimes, these intravitreal injections can cause air bubbles to form. Until the eye absorbs the bubbles, they will appear as floaters, sometimes persisting for weeks. Ophthalmologists use vitreoretinal surgeries to treat conditions such as macular degeneration, uveitis, and macular holes. Ironically, doctors sometimes also use vitreoretinal surgeries to remove floaters.
Some conditions that cause eye floaters and flashes are less blatant than others. For example, diabetes can eventually lead to various eye-related conditions such as diabetic retinopathy and diabetic macular edema. Cytomegalovirus (CMV) retinitis is a serious disease that frequently appears alongside immune system diseases like AIDS. CMV invades the retina and begins to damage the light receptors that enable sight. Though this is typically painless, it does cause floaters and specks to appear. CMV infections in HIV-positive individuals can be life-threatening if not treated early, and therefore require medical attention as soon as possible.
In addition to the diseases and events responsible for eye floaters, a few risk factors can increase the likelihood that a person will develop them. One of the biggest risk factors is age. Individuals over the age of 50 are more likely to have eye floaters, with the chance increasing significantly for people over 80. Another key risk factor is nearsightedness or myopia, which is the most common cause of vision issues for people under 40. People who had cataract surgery can also develop floaters and other vision problems.
Most floaters are a minor issue and will eventually settle along the bottom of the eye and out of sight. However, some signs can indicate that floaters are the result of a serious medical condition requiring emergency care. Primarily, any loss of vision accompanying floaters is serious. Other important signs include a sudden increase in the number of floaters, flashes of light, and eye pain. All these symptoms suggest retinal detachment, which must be treated quickly to prevent vision loss.
Because most floaters aren't harmful, doctors tend not to treat them directly, opting instead to treat the underlying condition. However, if the floaters interfere with a person's vision, physicians have a few options. The most common procedure is a vitrectomy. In this procedure, doctors insert a hollow needle into the eye and remove the vitreous, replacing it with salt water. However, this is an invasive procedure that may cause side effects such as bleeding and retinal tears.
In recent years, doctors have shifted to using a procedure called laser vitreolysis. It is safer than a vitrectomy because it is not nearly as invasive. A technician uses a machine to project a laser into the eye, through the pupil, and onto the floaters. This breaks the floaters apart or destroys them entirely, clearing the patient's vision. In patients under the age of 45, however, the floaters tend to sit too close to the retina for this procedure to safely eliminate them. In general, the risks of laser therapy include damage to the retina.
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