Why do I see floaters in my eyes?
A dark shape or line moving across your vision is known as an eye floater. Floaters in the eye are often a normal part of aging and usually do not require treatment. However, a sudden onset of floaters can be a sign of something more serious and should be evaluated by an eye doctor promptly.
A sudden "shower" of floaters might indicate an age-related condition called posterior vitreous detachment (PVD). This occurs when the vitreous humor, a gel-like substance in the eye, separates from the retina (the light-sensitive tissue at the back of the eye) more suddenly than usual. However, sudden floaters — especially with flashes of light or vision loss — could signal a retinal tear or retinal detachment (when the retina pulls away from the back of the eye). This can cause blindness without prompt treatment.
Floaters can also occur with eye inflammation (uveitis) or bleeding in the eye. People with diabetes may develop floaters due to diabetic retinopathy, where damaged blood vessels leak into the retina.
Having a good understanding of what causes eye floaters can help you figure out if they could be a sign of something more serious. However, if you experience them, it’s important to visit your eye doctor for a dilated eye exam.
What are eye floaters?
Eye floaters — clinically known as myodesopsias — are spots, flecks or squiggly lines that might appear when you're looking at something with a light or white background. The floaters may look like they're slowly moving around in your eye or vision.
Other types of floaters can have different shapes, including:
- Thready-looking lines
- Tiny shadows or clouds
- Spiderweb or cobweb shapes
Floaters form when the vitreous humor — a clear, gel-like substance that fills the center of the eye — shrinks with age, creating clumps that cast shadows on the retina. These clumps are often caused by the breakdown of collagen fibers within the vitreous. While floaters are more common with age, they can occur in younger individuals due to various underlying causes.
READ MORE: How can eye floaters be treated?
Possible causes of eye floaters
There are a number of different eye floater causes. Some occur naturally as our eyes age, while others can be a potential sign of a serious eye condition. Understanding the possible reasons for your eye floaters can help you decide whether to call an eye doctor or get medical attention.
Natural aging process
Because eye floaters are naturally considered a part of aging, they normally appear when a person is between 50 and 70 years old. However, floaters can occur at any age.
Other risk factors for seeing flecks and lines in your vision as you get older include:
- Being nearsighted (having myopia)
- Having diabetes
- Undergoing surgery for cataracts (clouding of the eye's natural lens)
- Having a history of retinal detachment and tears in your family
READ MORE: How to reduce eye floaters naturally
Posterior vitreous detachment (PVD)
As you age, your body changes, including your eyes. This includes the gel-like substance in the eye called the vitreous humor.
Over time, the vitreous humor shrinks and begins to pull away from the retina. This causes the formation of floaters within the vitreous humor and is called posterior vitreous detachment.
PVD causes clumps to form in the vitreous humor. These clumps, or eye floaters, glide around in the vitreous humor and appear as shadows in your vision.
In addition to eye floaters, you may also experience flashes of light in your eyes. This sensation is also caused by the vitreous humor tugging on the retina, but it's different from floaters. The sudden appearance of flashes, floaters or a dark curtain over your vision can be a sign of a serious eye condition — such as a retinal tear — that requires immediate treatment by a doctor.
PVD is relatively common and occurs in approximately 66% of adults aged 66 to 86. Most cases of PVD have mild symptoms, do not cause any vision loss or require treatment unless there is an underlying condition, such as a retinal tear. In some instances, floaters may disappear over time.
Nearsightedness (myopia)
People who have myopia or nearsightedness are at an increased risk of developing eye floaters.
Typically, when a person is nearsighted, the length of their eyeball from front to back is longer, which increases the likelihood of the vitreous humor pulling away from the retina. Myopia can cause PVD to occur earlier in life.
READ MORE: Is it normal for young people with myopia to have eye floaters?
Trauma to the eye
A more serious cause of floaters in the eye is eye trauma, such as:
- Eye injuries – An eye injury can cause changes to the vitreous, leading to floaters.
- Eye inflammation (uveitis) – Uveitis that affects the vitreous (intermediate uveitis) or retina (posterior uveitis) can cause floaters.
- Retinal infection (cytomegalovirus retinitis) – Floaters are one of the earliest symptoms of this type of infectious retinitis that damages the retina.
- Eye surgery – Certain types of eye surgery, such as cataract surgery, can cause PVD, potentially causing floaters.
Treatment for the underlying cause of floaters depends on the type of injury. Uveitis is typically treated with corticosteroids to reduce inflammation. This often starts with eye drops for mild cases and progressing to injections or oral steroids for more severe forms. Cytomegalovirus retinitis (CMV) is typically treated with antiviral medications.
Retinal detachment and tears
Both retinal tears and detachments can occur when the vitreous humor inside the eye shrinks and tugs on the retina, potentially causing damage to it.
A retinal tear is when pulling from the vitreous humor causes a small hole or break in the retina, allowing fluid to leak behind the retina. This can then lead to retinal detachment, as the fluid can cause the retina to separate from the back of the eye.
Both retinal tears and detachments are associated with a sudden increase in eye floaters and should be treated as a medical emergency.
Treatments like laser photocoagulation, cryopexy or surgery may be performed to repair the retina and help prevent further damage.
Vitreous hemorrhage
Vitreous hemorrhage is an eye condition where blood accumulates in the vitreous humor, which can cause floaters to suddenly appear in your vision. Other symptoms include a sudden decrease in vision. An eye doctor will need to look inside your eye to diagnose it, as it doesn’t change how your eye looks on the outside.
A number of underlying causes can lead to vitreous hemorrhage, including:
- Eye injury
- Damage to the eye’s blood vessels
- Diabetic retinopathy
- High blood pressure
- Anemia
- Eye cancer
- Wet age-related macular degeneration
While a mild vitreous hemorrhage can sometimes go away by itself, treatment may be needed. Your doctor may wait a few days to see if it resolves on its own. During this time, you will be asked to rest and avoid strenuous activities.
When treatment is necessary, it may include medications or laser treatments to address underlying issues, surgery to remove the vitreous humor (vitrectomy) or treating the condition that caused the bleeding.
When floaters appear suddenly
Gradually developing eye floaters like squiggly lines and dark or clear dots can be a normal part of the aging process.
However, if you suddenly notice a large increase in the number of new floaters in your vision or if eye floaters are accompanied by blurred vision, flashes, a dark curtain or eye pain, it’s important to call your eye doctor or visit an emergency room for immediate care. A sudden large shower of floaters in the eye is a possible sign of either a retinal tear or detachment, both of which can lead to vision loss if not treated.
Diagnosing the cause of eye floaters
If you’re unsure about what is causing your eye floaters, an optometrist, ophthalmologist or retinal specialist can examine your eyes to assess whether your floaters are a sign of something serious or not. Most floaters fade or become less noticeable over time.
A dilated eye exam is performed to check eye floaters, as it allows your eye doctor to view your retina to look for signs of a tear, detachment or other issues.
When to talk to an eye doctor
If you see floaters in your eyes, it’s important to make an appointment with an eye doctor so you can find the cause. They can perform a comprehensive dilated eye exam to find out why you're seeing clear or black spots, flecks or squiggly lines.
