Flashes and floaters of the eye are usually the result of age-related changes to the vitreous, which is the thick gel firmly attached to the retina from birth. During the aging process, however, the vitreous becomes thinner and more watery, and at some point pulls away from the retina. This is known as a posterior vitreous separation or detachment (PVD). During PVD, tissue debris that was once secure in the firm vitreous gel loosens and moves around, casting shadows on the retina.
When this occurs, patients experience visual disturbances in the form of flashes of light, or floaters (specks or strands across the field of vision). These symptoms are not typically a reason for undue concern, but should, nonetheless, be evaluated by an ophthalmologist.
Causes of Flashes and Floaters
Flashes occur as a result of pressure on the retina, the bundle of nerves in the back of the eye where images are detected and transmitted to the brain. Such pressure causes patients to see either flashing lights or lightning streaks. Floaters occur when collagen fibers move across the vitreous and into the field of vision, causing patients to see specks, strands, webs or other shapes as the fibers cast shadows on the retina. Flashes and floaters are most visible when looking at a plain, light background.
Beyond simple aging, floaters or flashes appear most often in eyes that are injured, inflamed or nearsighted, and can be a result of the following:
- Cataract or YAG laser surgery
- Diabetes
- Retinitis
- Nearsighted vision
- Eye infections
- A blow to the head
- Injury to the eye
- Spasm of small blood vessels
The spasm (sudden constriction) of small blood vessels in the brain is also associated with migraine headaches.
Diagnosing Flashes and Floaters
Most people who develop PVD do not suffer further complications. For a small percentage of people, however, PVD is caused by retinal tears. A retinal tear is quite dangerous because it can lead to retinal detachment, which can seriously threaten vision. A sudden onset of symptoms, or momentary blindness in one section of the field of vision, is cause for concern. Patients who experience either should seek immediate medical attention.
Because symptoms may be the same regardless of the cause of the problem, it is important that anyone experiencing unfamiliar disturbances in vision have an examination in which the pupils are dilated; this is the only way in which a retinal tear can be accurately diagnosed. This is one of the reasons that it is crucial for patients to undergo thorough eye examinations on a regular basis.
For patients initially diagnosed as having uncomplicated PVD, a small percentage will go on to have retinal tears within 6 weeks, so it is important that they follow up with their doctors. For patients with underlying causative conditions, such as illness or injury, other treatments may be necessary.
Treatment of Flashes and Floaters
Although flashes and floaters are usually harmless and do not need treatment aside from regular monitoring, patients bothered by disturbances in their vision, or those experiencing significant visual interference, require medical intervention.
When treatment is necessary to reduce the appearance of flashes and floaters, it requires surgery to replace the vitreous gel. This procedure, known as a pars plana vitrectomy, removes the natural vitreous and replaces it with fluid.
In the case of a retinal detachment, emergency treatment is necessary to prevent serious complications. With treatment, most patients, even those with retinal tears, are able to maintain healthy vision.
Frequently Asked Questions (FAQ) – Flashes and Floaters
1. What are flashes and floaters?
Flashes are brief bursts of light that appear in your vision, often seen in peripheral vision, and may look like lightning or streaks of light.
Floaters are small, shadowy shapes or spots that seem to drift through your field of vision. They are often more noticeable when looking at a bright background, such as a blue sky or a white wall.
2. What causes flashes in the eyes?
Flashes can be caused by the vitreous gel inside the eye pulling on the retina. This can happen as part of the natural aging process when the vitreous, a gel-like substance in the eye, shrinks or changes consistency. The flashes of light occur when the vitreous tugs on the retina or optic nerve.
3. What causes floaters in the eyes?
Floaters are caused by tiny clumps or strands of collagen forming within the vitreous gel. These clumps cast shadows on the retina, which you perceive as floaters. Floaters are often more noticeable as people age because the vitreous gel becomes more liquid and the clumps of collagen become more prominent.
4. Are flashes and floaters normal?
In many cases, floaters and occasional flashes are normal and can be a result of the natural aging process. However, a sudden increase in flashes or floaters, or if they are accompanied by a loss of vision or a curtain-like shadow in the field of vision, could indicate a more serious condition, such as a retinal tear or detachment.
5. When should I be concerned about flashes and floaters?
You should seek medical attention immediately if you experience:
- A sudden increase in floaters or flashes
- A new, large floater or shadow in your vision
- Loss of peripheral vision or a curtain-like shadow covering part of your vision
- A sudden decrease in vision
These could be signs of serious eye conditions, such as retinal tears or retinal detachment, which require prompt treatment.
6. Are flashes and floaters a sign of retinal detachment?
Flashes and floaters can be symptoms of retinal detachment, but they are not always linked to this serious condition. Retinal detachment occurs when the retina pulls away from the back of the eye, which can lead to permanent vision loss if not treated promptly. If you notice flashes or floaters along with vision changes such as a shadow or curtain in your vision, seek immediate medical attention.
7. How are flashes and floaters diagnosed?
An eye care professional will perform a thorough eye exam to diagnose the cause of flashes and floaters. This may include:
- A dilated eye exam, where the pupil is widened with drops to allow a better view of the retina and vitreous gel.
- OCT (optical coherence tomography), a non-invasive imaging technique that helps visualize the retina and any potential issues.
- Ultrasound or fluorescein angiography may be used if retinal detachment or other serious conditions are suspected.
8. Can flashes and floaters be treated?
Treatment for flashes and floaters depends on the underlying cause:
- If the flashes or floaters are caused by aging changes in the vitreous, no treatment may be necessary. Over time, many floaters become less noticeable.
- If a retinal tear or detachment is diagnosed, prompt treatment is necessary. This may involve laser surgery or cryotherapy to repair the retina, or more advanced procedures for retinal detachment, such as vitrectomy or scleral buckle surgery.
9. Will floaters go away on their own?
In many cases, floaters become less noticeable over time as the brain adapts to their presence. However, floaters don’t always disappear completely. If they are persistent and interfere with vision, treatments like laser therapy or vitrectomy (a surgical procedure) may be considered in severe cases.
