5 most common causes
What are eye flashes?
Most people experience a flashing light or eye floater in their vision at some point in their life. Flashing lights can be bright, colorful changes that look like a kaleidoscope or they may look like bright spots that are similar to when your photo is taken with a flash.
Floaters are typically cloud-like spots or shadows in the vision that can be light or dark colored.
Both visual changes are caused by a problem somewhere in the eye or vision pathway in the brain. These can occur with aging, but a number of diseases can also cause them. Because some serious causes may permanently affect vision, it’s important to see an eye doctor (ophthalmologist).
The main causes of eye flashes and floaters include: posterior vitreous detachment, migraine headaches, retinal tears or detachments, type 2 diabetes, or macular degeneration.
What can you do about floaters and flashers in the eye?
“Keep a written record of symptoms: when they began, how they change, how frequently they are occurring, or any other symptoms they may be associated with.”—Dr. Karen Hoerst
1. Posterior vitreous detachment
- Floating dark spots (can look like strings or cobwebs)
- Flashes of light (can look like lightning or camera flashes)
- Floaters are more noticeable when looking at a plain light-colored background in bright light.
- Symptoms are mild and come and go.
Posterior vitreous detachment (PVD) is the most common cause of floaters and flashing lights. It starts happening between the ages of 50 and 70. It is caused by the gel-like substance in the eyes (known as vitreous) partially liquifying and shrinking with age.
When this occurs, it can pull on and separate from the retina at the back of the eye. The parts of the gel that move around the eye when this occurs can cause floaters. When it tugs at the retina, it can cause flashes of bright light. This can also increase risk of retinal detachment.
Treating posterior vitreous detachment
Symptoms of floaters can get better with time as the gel-like pieces settle to the bottom of the eye. However, if you have ongoing problems with vision and it is affecting your quality of life, you may want to consider surgery. There are different types of surgeries, but the goal is to stabilize the retina if you have a retinal tear or detachment.
- Visual symptoms: bright or colorful spots, sparkles or shimmering lights, zigzagging lines, or stars
- Sound and light sensitivity
- Severe headache
Migraine causes severe headaches that usually last from 4 to 72 hours, and people often have other symptoms like nausea and light or sound sensitivity. You may notice visual symptoms just before or during a migraine headache and are known as visual auras. Migraine with aura occurs in 25% to 30% of people with migraines. Some people have visual auras but no headache, which is known as ocular migraine.
If your migraine symptoms are not frequent, you may be able to treat them with over-the-counter (OTC) pain-relievers. But taking pain relievers too often can actually cause more headaches, called medication overuse headaches or “rebound” headaches. Try to limit use to less than 3 times per week in order to avoid rebound headaches.
If severe and frequent migraines are a problem, your doctor may prescribe a “rescue” medication to treat pain and help stop the migraine after it has started. Some of these medications are called triptans.
They may also prescribe a daily medication that can help reduce the number of migraines in people who get chronic migraines. Some of these medications are pills that were initially approved for other things like blood pressure or seizures.
A new type of medication, called CGRPs (Calcium Gene Receptor Protein) inhibitors, are injected or given intravenously every few months to reduce the number of migraines people experience.
Injections of botulinum toxin (Botox) can also help prevent migraines. Sometimes your healthcare provider may combine medications in order to better treat your symptoms.
Are flashing lights in eyes serious?
“A common misconception is that flashes of light and floaters are always harmless. While this is usually true, there are certain signs and characteristics to look for that would tell you how urgently to be seen by an ophthalmologist.”—Dr. Hoerst
3. Retinal tear or detachment
- Many new floaters or showers of floaters
- A lot of bright flashes, not improving
- Sometimes it looks as though a curtain is dropping down over your field of vision
- Side or sides of your vision become dark
- Complete vision loss in one or both eyes
The retina receives and organizes visual information and sends it to the brain to interpret what you see. A retinal tear usually occurs from vitreous (the gel-like substance in the eyes) pulling the retina or from injury to the eye. It causes a part of the retina to separate from the back of the eye.
There is a high risk of the tear getting larger and leading to a bigger separation called a retinal detachment. The initial symptoms of a retinal tear, including flashing lights and loss of vision, are similar to a detachment but tend to be more mild.
Treating retinal tear or detachment
A retinal detachment deprives the retina of oxygen and nutrients and is considered an emergency. Retinal tears may or may not need immediate intervention, depending on symptoms or the size of the tear.
Either way, you should be seen by an ophthalmologist to determine the appropriate treatment and how urgently this treatment must be done.
- Blurry or hazy vision, usually in both eyes
- Spots/floaters or flashes
- Difficulty seeing at the center of vision
- Trouble seeing at night
- Frequent urination
- Increased thirst
Diabetes mellitus is when you have high levels of glucose, or sugar, in your blood. Uncontrolled and ongoing diabetes can cause many complications, including damage of small blood vessels, such as those of the retina. This is called diabetic retinopathy.
Diabetes damages vision in two ways. First, the blood vessels can become leaky, causing direct damage to the retina. And because of damage to blood vessels, the eye can also start to form new blood vessels. But these are more likely to leak blood or other fluid, which causes vision to be hazy or blurry. These new blood vessels can also cause scars that can tug at the retina and cause a retinal tear or detachment. This may cause you to see spots, flashes of light, or vision loss.
The goal of treating diabetes is to control blood sugar levels. The better your blood sugar levels are, the less likely you are to develop complications of diabetes. People manage it through medications like insulin, changes in their diet, and regular exercise. Controlling blood pressure, cholesterol levels, and maintaining a good weight can also help prevent complications of diabetes.
People with diabetes should have a yearly eye exam by an ophthalmologist to monitor the health of the eyes regularly. If your doctor notices any symptoms of diabetic retinopathy, they may recommend medications that help prevent the development of new, problematic blood vessels.
5. Macular degeneration
- Distorted or darkened central vision
- Loss of central vision
- Floaters or flashing lights
Macular degeneration occurs when the arteries to the macula (a part of the retina), harden with age. This leads to less oxygen and nutrients to this area of the eye that is responsible for clear and sharp central vision.
There are two forms of AMD: Dry AMD is much more common. Wet AMD is more damaging.
Treating macular degeneration
AMD is often treated with combinations of antioxidants called "AREDS" and "AREDS2." These contain vitamin C, vitamin E, and zinc, beta-carotene or lutein, and zeaxanthin. The treatments can slow the progression of the disease.
Wet AMD may be treated with injections into the retina with medications called VEGF-inhibitors. These decrease the growth of abnormal blood vessels.
Other possible causes
Other causes of eye flashes include trauma to the eye, rubbing your eyes, looking at bright light, or having cataract or other eye surgery.
When to call a doctor
Though it is not uncommon to have flashes of light and floaters, it is important to get evaluated by an ophthalmologist (an eye physician) to rule out other causes that may need treatment.
- Flashes or floaters that do not subside
- Increased shadows in certain areas of your vision
What do flashing lights in vision look like?
“Floating shadows or dark spots in vision, bright flashing lights, looks as though they have stared at bright light or the sun and can see spots floating, painless, stringy or like cobwebs, like flashes from a camera or lightning.”—Dr. Hoerst
When to go to the ER for eye flashes
Go to the ER if you have any of these symptoms:
- Any sudden new floaters or showers of floaters
- Bright flashes that are continuous or not improving or are increasing in frequency
- If it looks like a curtain is dropping down over your field of vision
- If any area of your vision becomes dark
- Complete vision loss in one or both eyes
- Any trauma to the eye
- A bad headache and eye flashes or floaters affecting both eyes
Eye flash treatments
Floaters and eye flashes should be monitored by an ophthalmologist to rule out eye damage. If floaters and eye flashes are infrequent, you can help reduce their occurrence with the following steps:
- Minimize screen time
- Wear sunglasses outside
- Gently massage your temples
- Drink plenty of water
- Rest your eyes
Other treatments you may have
- Dilated eye exam (drops are placed in your eyes to dilate the pupils so the doctor can examine them clearly)
- Eye pressure test
- Vision test
- Imaging of eye
- Medications, depending on the disease
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