Flashing circle in vision

Why Do I See Halos Around Lights?

Halos around lights are caused by diffraction, or bending of the light entering your eye. There are many eye conditions that can cause this to happen. These include:


A cataract is a cloudy area that forms in the lens of the eye. Cataracts develop slowly and are common in older people. Clouding of the lens can cause diffraction of light entering the eye, which means you’ll see halos around light sources.

Other symptoms of cataracts include:

  • blurry vision
  • trouble seeing at night
  • increased sensitivity to glare
  • double vision

Cataract surgery

Cataract surgery involves replacing your cloudy lens with a custom intraocular lens (IOL). Seeing halos around lights can sometimes be a side effect of the new lens.

Fuchs’ dystrophy

Fuchs’ dystrophy is an eye disorder that causes the clear layer on the front of your eye (cornea) to swell. The abnormalities in the cornea can cause someone with Fuchs’ dystrophy to see halos around lights.

Other symptoms include:

  • sensitivity to light
  • cloudy vision
  • swelling
  • difficulty driving at night
  • eye discomfort

Fuchs’ dystrophy is usually inherited, and symptoms don’t usually appear until people reach their 50s or 60s.


Glaucoma is a condition caused by optic nerve damage related to high pressure in the fluid circulating in the front of the eye. Glaucoma is a leading cause of blindness in the United States.

One type of glaucoma known as acute-angle closure glaucoma is considered a medical emergency. Symptoms of acute glaucoma usually appear suddenly. If you suddenly start seeing halos or colored rings around lights, it could be a sign of acute glaucoma.

Other symptoms include

  • blurred vision
  • eye pain and redness
  • nausea
  • vomiting
  • headache
  • weakness

See a doctor immediately if you have any of these symptoms.


Kerataconus occurs when the cornea progressively thins and causes a cone-like bulge to develop on the eye. This results in visual impairment and may cause you to see halos around lights. The cause of kerataconus isn’t known.

Other signs and symptoms of keratoconus include:

  • blurred vision
  • frequent changes in eye glass prescription
  • light sensitivity
  • difficulty driving at night
  • eye irritation or pain


It’s possible for your eyes to become sunburned if they’re exposed to too much of the sun’s ultraviolet (UV) light. In addition to seeing halos around lights, the most common symptoms of sunburned eyes, or photokeratitis, include:

  • pain, burning, and a gritty feeling in the eyes
  • sensitivity to light
  • headache
  • blurred vision

These symptoms usually go away on their own within a day or two. See a doctor if they don’t subside or if the pain is severe.

LASIK surgery

Some corrective eye procedures, such as LASIK (laser in-situ keratomileusis) surgery, can also result in halos as a side effect. The halos usually only last for a few weeks after the surgery. More modern types of LASIK are less likely to cause this side effect.

Ocular migraine

An ocular migraine is a rare type of migraine that causes visual disturbances. Along with a severe headache, people who experience ocular migraines may see flashing or shimmering lights, zigzagging lines, and halos around lights.

Wearing glasses or contact lenses

Wearing corrective lenses, like eyeglasses and contact lenses, can also cause a halo effect when looking at a bright source of light. Researchers are working on developing contact and intraocular lenses that minimize the halo effect.

Dry eyes

When the eye’s surface is too dry, it can become irregular, and light entering the eye can scatter. This can cause you to see halos around lights, especially at night.

Symptoms of dry eye include:

  • stinging
  • burning
  • pain
  • redness of the eye

Symptoms are often made worse by reading, using a computer, or being in a dry environment for a long period of time.

Floaters, Flashing lights, Rainbows, Abnormal Color Vision, Distorted Vision

Ocular Symptoms and Conditions: Floaters, Flashing lights, Rainbows, Abnormal Color Vision, Distorted Vision

This page discusses unusual visual phenomenon such as floaters and different types of flashing lights. Other visual abnormalities such as seeing rainbows around lights, abnormal color vision, and distorted vision are discussed as well.

The first grouping of abnormalities give symptoms of floaters or flashing lights. Separate sections on Rainbows, Abnormal Color Vision, Distorted Vision, and Tunnel Vision follow.

Conditions Discussed on this Page:

  • Floaters and Flashing Lights
  • Vitreous Detachment
  • Retinal Tear
  • Uveits (inflammation in the eye)
  • Entoptic Phenomenon
  • Eales’ Disease
  • Ophthalmic Migraine
  • Transient Visual Obscurations
  • Rainbow Vision
  • Abnormal Color Vision
  • Distorted Vision
  • Tunnel Vision
  • Retinitis pigmentosa

Floaters and Flashing Lights

“Floater” is a common term referring to seeing abnormal spots moving in the vision. It is important to be careful and very specific in how this is described as the description itself can help lead to the proper diagnosis. Some people use the phrase, “I feel like there is something moving in my eye”. However, this phrase could also be used to describe the physical sensation of something irritating the surface of the eye (a foreign body sensation), and if the meaning of this phrase is not clarified, the wrong diagnosis could be made.

Many people are born with “floaters” that they see from time to time, especially when looking at a blank background or laying back looking at a bright daytime sky. What is being seen in this case is most likely the remnant of a vessel that existed between the optic nerve and lens of the eye before birth, which degenerates into a nearly transparent “worm-like” opacity that moves about in the vitreous. People that have this normal variation are generally familiar with its appearance to them, and it usually changes very little throughout life.

A change in floaters or a new floater is reason for concern, as it can be associated with disease conditions within the eye, especially if associated with flashes of light. These new floaters might also be nearly transparent, but they may appear more like gnats or insects flying in the vision or crawling on the floor. Sometimes they are described like cobwebs in the vision. The examining doctor can often actually visualize what the new floater is during an eye examination. Note that something floating in the tear film of the eye or a foreign body on the surface of the eye will not be visualized as a floater (although it might blur the vision). Similarly, except in cases of severe trauma, objects cannot enter the eye from the outside to cause floaters.

“Flashing” is a symptom of seeing a flash of light in the vision. This is rarely seen as a normal visual phenomenon throughout life. It is important to distinguish the nature of the flash, as one type of flash is very brief and transient, like a lightning bolt, and other flashes are more continuous and can last for minutes or hours. Sometimes flashing might also be seen with head or eye movement. Sometimes after cataract surgery with lens implants, light might strike the lens implant at a certain angle that might cause a flash in the peripheral vision, and sometimes light might strike a lens implant in such a way that it can appear reflective to another person looking at the pupil of the eye.

Vitreous Detachment

The vitreous is a gel-like fluid which fills most of the eye. As people age, this vitreous becomes more and more liquefied. The vitreous has loose attachments to the retina, and more firm attachments to the optic nerve. At some point in a person’s life, the vitreous liquefies enough to shift position in the eye. When this occurs, usually between age 50 and 70, the back edge of the vitreous will pull forward away from the optic nerve and retina, leading to a “posterior vitreous detachment”. This is generally a normal process, although it may happen abnormally early in cases of high nearsightedness or trauma. As the vitreous detaches, it tugs on the retina and optic nerve. This is perceived as a flash of light, similar to a lightning flash in the corner of the vision. It may occur especially with eye movement, since the vitreous moves in the eye. Debris pulled off of the optic nerve and retina are then seen as floaters, suspended in the vitreous above the retina. Sometimes this is described as a cobweb, a net, a string, or a fly over the vision.

These symptoms usually resolve over a period of days to weeks, although some people will continue to see the floaters for a longer period of time. The important thing is to determine that the retina is healthy as the vitreous detaches. This requires a careful dilated examination of the retina to look for tears, or other areas which may be at risk for tearing. A retinal tear can then lead to retinal detachment, if not treated. Thus, people experiencing these symptoms should be examined by an ophthalmologist as soon as possible. (Note, only about 1 in 10,000 cases of vitreous detachment lead to retinal detachment, but it still is one of the most common causes of retinal detachment.) It has been found that the second eye will also develop a vitreous detachment within 1-2 years of the first eye, and this should be examined as well when it happens.

Retinal Tear

A tear in the retina can occur with vitreous detachment (see discussion above), with trauma or eye injury, or in areas at risk for a retinal tear, such as “lattice degeneration”. The symptoms of a retinal tear usually are of a flash of light in the peripheral vision followed by floaters. The floaters may be debris, but may also be blood, if the tear extends through a retinal blood vessel. Blood in the vitreous is often perceived as millions of tiny floaters, or actual blobs in the vision if the hemorrhage is more significant. Symptomatic retinal tears should be treated by laser to prevent retinal detachment. Sometimes a retinal tear is discovered incidentally as part of an eye examination. These may or may not need to be treated.

Uveits (inflammation in the eye)

Uveitis refers to a large group of disorders which cause inflammation within the eye. A similar condition, iritis, usually refers to inflammation involving the front structures of the eye associated with pain, redness, and sensitivity to light. In this discussion, uveitis could also have these symptoms, but mainly consists of inflammation involving the back structures of the eye (the retina, choroid, and optic nerve). Inflammatory debris liberated into the vitreous leads to the visualization of floaters. If this liberation continues, the vision may become substantially hazy and blurred.

There are numerous conditions leading to uveitis, and many have floaters and blurred vision as predominant symptoms: sarcoidosis, toxoplasmosis chorioretinitis, ocular histoplasmosis, multifocal choroiditis, pars planitis, endophthalmitis, syphilis, candidiasis, viral uveitis, Vogt-Koyanagi-Harada syndrome, multiple sclerosis, and HIV related uveitis.

Entoptic Phenomenon

Entoptic phenomenon is a normal phenomenon that some people may become suddenly aware of. This sudden awareness may lead to the idea that there is a problem with the eyes, when actually there is not. The entoptic phenomenon can be seen especially when looking at a bright blue sky. Small, rapid pin-point sparks of light can be seen darting about in the central vision. Some people may think that these sparks are floaters. In reality, they may represent white blood cells moving through the blood capillaries of the retina. This is a normal finding, and actually indicate normal retinal function.

Eales’ Disease

Eales’ Disease is a rare disorder primarily affecting young adult males in their 30’s to 50’s. 80% of those affected are male, and usually both eyes are affected. There is no known cause for the disease, and no known association with any medical disorder (although one study noted balance dysfunction and hearing loss in 24% of patients).

In Eales’ Disease, there is inflammation of the retinal vessels, where there is visible sheathing of the vessels and inflammation of the vessels. This can lead to obstruction of the vessels, hemorrhages into the retina and vitreous, and occasionally retinal detachment (in severe cases). There may be no symptoms of this disease, or one may see floaters, or develop a loss of vision if vitreous hemorrhage or retinal detachment occur.

Treatment is usually aimed at eliminating the risk of hemorrhage through retinal laser treatments. Oral anti-inflammatory agents may also be helpful.

Other Visual Phenomena:

Ophthalmic Migraine (also called acephalgic migraine, migraine aura without headache, amigrainous migraine, isolated visual migraine, ocular and optical migraine)

Migraine headaches may be preceded by a visual “aura”, lasting for 5 to 30 minutes (most commonly around 15 minutes), and then proceeding to the headache. Some people, however, experience the aura but do not have a headache. This visual aura can be very dramatic. Classically, a small blind spot appears in the central vision with a shimmering, zig-zag flicker light inside of it (“scintillating scotoma”). This enlarges, and moves to one side or the other of the vision, over the 5 to 30 minute period. When it is large, this crescent shaped blind spot containing this brightly flashing light can be difficult to ignore, and some people fear that they are having a stroke. In reality, it is generally a harmless phenomenon (with one exception noted below), although many people subsequently get the migraine headache. Since migraine originates in the brain, the visual effect typically involves the same side of vision in each eye, although it may seem more prominent in one eye or the other. It is usually mainly perceived as occurring in the eye in which is occupies the temporal (outside) field of vision. The visual phenomenon would also be perceived in the nasal field of vision of the other eye.

Some people get different variations of this phenomenon, with the central vision being involved, or with the visual effect similar to “heat rising off of a car”. Some people describe a “kaleidoscope” effect, with pieces of the vision being missing. All of these variations are consistent with ophthalmic migraine. There are many examples of “visual migraine” that have been drawn by patients available on the internet.

Please note that this is different from a condition known as “retinal migraine”. A retinal migraine is a spasm of the artery entering the eye and leads to a temporary near-total loss of vision (a black out of the vision). This is different from “visual migraine”, which originates from the brain and is perceived bilaterally in the vision.

A possible risk factor in women for stroke: Recent studies have found that women especially under age 45 with recent onset of probable migraine with visual symptoms (within the prior year) were almost seven times more likely to have a stroke compared to women with no history of migraine. In addition, women who also smoked and used oral contraceptives had seven times the risk of stroke than women who had probable migraine with visual symptoms alone. Read more about this study here.

Transient Visual Obscurations

  • A transient visual obscuration is a temporary or fleeting dimming of vision that can affect one or both eyes. It differs from Amaurosis fugax, which is a more substantial black-out of some or all of the vision for a longer period of time.
  • Transient visual obscurations have been associated with increased intracranial pressure, specifically Idiopathic Intracranial Hypertension. This condition also has symptoms of headache and sometimes double vision.
  • In multiple sclerosis, some people will have a transient decline in vision related to exercise or increased body temperature, such as from bathing in a hot tub. This is known as Uhthoff’s phenomenon.
  • In some cases of vertebral artery insufficiency or obstruction, people will experience transient dimming of the vision, often with a sensation of imbalance.
  • In cases of orthostatic hypotension, there can be a drop in cerebral blood flow associated with standing rapidly from a seated or lying position. This can lead to a transient dimming of vision with a sensation of imbalance or syncope. Some anti-hypertensive medications can worsen this symptom.
  • Some cases or transient visual obscurations have occurred after consuming a very heavy meal, or after sexual intercourse.

Rainbow Vision

Seeing rainbows around lights, especially at night, usually indicates swelling of the cornea. This may occur from a variety of causes which are discussed under Corneal Edema. Cataract can sometimes cause this also.

Abnormal Color Vision

Color vision is perceived mainly by the macula, which is the central vision portion of the retina. Thus any disorder affecting the macula may cause a disturbance in color vision. However, about 8% of males and 0.5% of females have some version of “color blindness” from birth. Usually this is an genetically inherited trait, and is of the “red-green confusion” variety. The reds, browns, olives, and golds may be confused. Purple may be confused with blue, and pastel pinks, oranges, yellows, and greens look similar. Usually both eyes are affected equally.

There are many rare macular retinal disorders that can lead to a loss of color vision, and many of these syndromes are inherited as well. There may also be a problem with a generalized loss of vision with these problems as well. Other retinal problems can lead to a temporary disturbance of color vision, such as Central serous Chorioretinopathy, Macular Edema of different causes, and Macular Degeneration.

Certain types of cataract can gradually affect the color vision, but this is usually not noticed until one cataract is removed. The cataract seems to filter out the color blue, and everything appears to be more blue after cataract extraction. Optic nerve disorders such as Optic Neuritis can greatly affect color vision, with colors seeming washed out during or after an episode, especially the color red.

Distorted Vision

Distortion of vision refers to straight lines not appearing straight, but instead bent, crooked, or wavy. Usually this is caused by distortion of the retina itself. This distortion can herald a loss of vision in macular degeneration, so anyone with distorted vision should seek medical attention by an ophthalmologist promptly. Other conditions leading to swelling of the retina can cause this distortion, such as Macular edema and Central serous Chorioretinopathy.

An “Amsler grid” can be supplied by an ophthalmologist so that the vision can be monitored for distortion in people who may be predisposed to this problem.

Tunnel Vision

“Tunnel vision” implies that the peripheral vision, or side vision, is lost, while the central vision remains. Thus, the vision is like looking through a tunnel, or through a paper towel roll. Some disorders that can cause this include:

  • Glaucoma – severe glaucoma can result in loss of nearly all of the peripheral vision, with a small “island” of central vision remaining. Sometimes even this island of vision can be lost as well.
  • Other Optic Nerve Conditions – There are a number of sometimes hereditary optic nerve conditions that can lead to a severe decrease in peripheral vision. Often both eyes are affected, and the patient’s visual impairment may be severe enough to require assistance with ambulation (cane, service dog). In some cases the central vision can still be normal in spite of the peripheral vision loss.
  • In some cases extensive laser photocoagulation is required to treat vascular conditions of the eye such as proliferative diabetic retinopathy and central retinal vein occlusions. This often leads to a near total loss of peripheral vision with sparing of the central vision. This can also occur as a complication of the disease processes themselves, due to a loss of retinal blood supply.
  • Following retinal detachment surgery there are many cases where there may be a significant loss of peripheral vision.
  • Stroke – a stroke involving both sides of the visual part of the brain may eliminate nearly all of the peripheral vision. Fortunately, this is a very rare occurrence
  • Retinitis pigmentosa (see below)

Retinitis pigmentosa

Retinitis pigmentosa is usually a hereditary disorder which can be part of numerous syndromes. It is more common in males. The peripheral retina develops pigmentary deposits, and the peripheral vision gradually becomes worse and worse, leading to “tunnel vision”. The central vision can be affected eventually as well. People with this problem may have trouble getting around in the dark. Cataract can be a complication as well. There is no known treatment for this disorder, and supplements of Vitamin A have not been proven to help.

What are flashes?

Flashes are unexplained brief lights seen in one or both eyes. They often occur on the edges of vision and they are fairly common. Each flash, which can vary from a bright light to almost a sparkle, lasts a varying length of time. Periods of flashing can go on for several months. The symptoms are often most noticeable when going from a light to a dark room.

What causes flashes?

Flashes are most commonly due to age-related changes in the vitreous humour. The vitreous humour is the jelly-like substance which fills the inside of the eye, between the lens and the retina. The vitreous humour is contained in a fine membrane and this is attached to the retina at the back and the lens at the front.

As we age, the vitreous humour shrinks and as it does so it can pull on the retina. This can cause flashes because the pulling triggers nerves in the retina and they send signals to the seeing nerve (optic nerve). Eventually the vitreous membrane tends to pull right off the retina, a condition called posterior vitreous detachment. This condition is harmless in itself, and in fact it happens to almost everyone eventually. The vitreous is detached from the retina in 75% of people aged over 65 and this is usually harmless.

The flashes of vitreous detachment may occur in one or both eyes. If they occur in both eyes this is because the same thing is happening in each eye separately (but since your eyes are usually very similar this is not unlikely to occur at the same time). Sometimes, as the vitreous pulls on the retina, it can tear it, causing a retinal tear or a retinal detachment. However, most vitreous detachment does not harm the retina.

Conditions which affect the retina may also cause flashes. These include diabetic eye disease and sickle cell disease. Again, these can affect one or both eyes.

Flashes can also relate to migraines. Some people with migraine experience flashing lights. Usually, in migraine, these occur in both eyes simultaneously. They can last up to an hour and tend to increase to a maximum before fading away and being replaced by a headache, which is typically one-sided and which may or may not be severe.

Charles Bonnet syndrome is a condition experienced by people, usually elderly people, whose vision is deteriorating. The brain, deprived of real visual information, can make things up instead, particularly in conditions of low light. Patients may sometimes see flashes, although more frequently they see complex visual images like children or animals, which can look very real.

Can flashes be serious?

Most flashes are caused by changes in the vitreous humour which are related to age and which are harmless. Occasionally flashes can be a sign that the retina is at risk of being torn or detached. Increasing, persistent or constant flashes all suggest strong pulling on the retina and may mean that you are at risk of retinal damage. Flashes accompanied by a shadow coming down over your vision is suggestive of retinal detachment.

For further detail see the separate leaflet called Retinal Detachment.

Some people are at greater risk of retinal detachment than others, including those who have already had a retinal detachment in the other eye, those with inflammatory eye disorders such as uveitis, or degenerative conditions of the retina, those who have had significant eye trauma or surgery, and those with a family history of retinal detachment. People who are extremely short-sighted (correction more than -6.00D – your optician can tell you what your correction is) are at higher risk, as the globe of their eye tends to be longer so that the vitreous is more likely to pull away.

What are floaters?

Floaters are shapes (opacities) floating in the field of vision. They may look like spots, threads, spiders or cobwebs. They move as you move your eye and can seem to dart away when you try to look at them. They drift about inside the eye rather than staying still. They tend to be more obvious when bright objects, such as a blue sky, are being viewed.

Most floaters are also caused by changes in the vitreous humour. Most commonly this is due to normal ageing of the eye, when opacities form in the clear jelly and drift around. These kinds of floater are not associated with flashes or reduction in your vision and they tend to come on gradually. They also tend to ‘settle’ at the bottom of the eye, below the line of sight. After a while you will find them less noticeable. They are more common in those who are short-sighted, those who have had eye surgery and those who have diabetic eye disease.

Floaters can also occur after posterior vitreous detachment. In this case there will be a sudden obvious increase in the number of floaters. Flashes may also occur. Again, there should be no loss of vision and most cases settle without causing any problems.

Bleeding into the vitreous humour (vitreous haemorrhage) will also lead to the formation of floaters. However, in this case the floaters represent blood in the jelly. If the bleeding is major then vision may be affected. For more information on this condition see the separate leaflet called Vitreous Haemorrhage.

Floaters will result from any internal damage to the back of the eye. Retinal tears and retinal detachments also cause floaters, and these will vary with severity, depending on the severity of the damage.

Less common causes of floaters include inflammation of the eye (posterior uveitis) and, more rarely still, tumours affecting the eye.

Are floaters serious?

Floaters are usually not serious. However, you should see your doctor or optician, or visit the A&E department, if any of the following apply:

  • They come on suddenly.
  • There are large quantities of them.
  • They are particularly disturbing.
  • They are associated with other eye symptoms such as pain, severe headaches, changes in your vision, grey shadows in your vision or with new onset of flashes.
  • You have previously experienced retinal detachment, have had recent eye injury or eye surgery, have other eye conditions affecting the retina, or you have very high short-sightedness (myopia).
  • You already have vision in only one eye because of a prior condition, and you experience any new symptoms in your vision.

What are haloes?

Haloes are rainbow-like coloured rings around lights or bright objects. They usually occur because there is extra water in the layers of the eye. The most common and important cause of this is acute glaucoma. If you have glaucoma, you have increased pressure in your eye. This is a very painful condition which can threaten your sight if not treated promptly. However, another cause – chronic glaucoma – comes on more quietly and is not painful.

Many other conditions can cause you to experience haloes. These include watering or tearful eyes, overuse of contact lenses, cataracts and opacities in the vitreous humour. Some prescribed medicines may also cause you to see haloes, including digoxin and chloroquine.

Are haloes serious?

Because haloes can be a sign of increased pressure in your eye (glaucoma) then it is important you see your doctor or optician if you develop persistent haloes. It is also important that you do not drive in conditions where haloes may be affecting your vision – for example, when driving at night. If you have any doubts about your fitness to drive it is your responsibility to speak to the DVLA, who will advise you.

Who develops flashes, floaters and haloes?

Most people will notice occasional floaters, as there are often small opacities and crystals in the vitreous. Because more marked floaters, together with flashes and haloes, are mostly caused by conditions occurring naturally in older eyes, most people who experience them are over 60 years of age, although occasional floaters are not uncommon in people in their 40s and 50s.

Children and young adults may also experience flashes, floaters and haloes, particularly if there has been trauma or surgery to the eye or if they have other existing eye disease. These might include inflammatory conditions of the eye like uveitis, and conditions which can affect the retina like sickle cell disease and the form of retinopathy that can affect very premature babies.

When should I worry about flashes, floaters or haloes?

You should seek urgent advice about floaters and flashes if they are very marked or sudden in onset. You should also seek urgent advice if they are associated with pain, or changes in your vision, of if both floaters and flashes are occurring together. You should always seek advice if you develop persistent haloes. You should seek advice for any new symptoms, even if less severe than this, if you have previously lost the sight in one of your eyes, so that your new symptoms affect your only functioning eye.

Your first port of call, depending on the severity and timing of your symptoms, may be your optician, GP surgery or A&E department. Most opticians are able to check the pressures in your eyes in order to rule out glaucoma. Many will have equipment to allow them to fully examine the back of your eye for signs of damage to the retina. This equipment (called a slit lamp) is also available in A&E departments. Most GPs do not have slit lamps but your GP will be able to tell you if your symptoms suggest that you need to be seen by an optician or in A&E.

Why do I see rings or flashing lights in my field of vision?

If you see flashes of light in your peripheral vision, or you notice rings of light or halos in your line of sight from time to time, it is wise to book an appointment with your optometrist.

What could flashes in my vision mean?

There are a number of reasons why you may see what appear to be flashes of light. In many cases, halos and glare occur in your field of vision when there is a sudden change in light – for example, if you come out of a dark cinema into the bright sunlight. This is a normal response to bright lights, and will fade as your eyes adjust to your new surroundings. For some people, flashing circles in their peripheral vision go hand-in-hand with severe headaches or migraines. Make note of any other symptoms – like headaches – you are experiencing, as this can help your optometrist make an informed diagnosis. Flashes and lights could also be a sign that your glasses or contact lens prescription needs to be changed – as soon as your vision is corrected, the problem will likely disappear. If you are seeing halos in your field of vision, this could also be a symptom of cataracts. Others may experience flashing, rings of light or halos as a result of problems with the vitreous, which is the gel-like fluid inside your eye that liquefies with age. Sudden flashes could indicate a very serious issue – retinal detachment – which should be treated as an emergency.

What can I do to treat my symptoms?

If you only notice flashes when moving from dark conditions into bright sunlight, the right eye protection may be all that you need. But other conditions may require treatment from your optometrist. You may be given a new prescription, referred for further testing, or your optometrist may ask you to make more frequent appointments so that your symptoms can be closely monitored.In certain cases, surgical procedures may be required to correct the problem – your optometrist will explain the steps you need to take.

Eyes, flashing lights in the: There are a number of causes of spontaneous flashing light sensations in the eye. A sensation of flashing lights can be caused when the vitreous (the clear, jelly-like substance that fills the middle of the eye) shrinks and tugs on the retina. These flashes of light can appear off and on for several weeks or months. With age, it is more common to experience flashes. They usually do not reflect a serious problem. However, if you notice the sudden appearance of light flashes or a sudden increase in flashing lights, you should see your ophthalmologist immediately to see if the retina has been torn or if there is another cause. Flashes of light that appear as jagged lines or “heat waves” in both eyes, often lasting 10-20 minutes, are different. They are usually caused by migraine, a spasm of blood vessels in the brain. Jagged lines or “heat waves” can also occur without a headache in which case they are termed ophthalmic migraine, or migraine without headache.



What causes dry eyes? See Answer

The term ocular migraine implies that you should get a headache afterwards. That’s not always the case. Some people do have migraine headaches after seeing these images in their vision but not everyone. You may have heard of people getting an aura that tells them they’re about to get a migraine. That’s essentially what this is. Auras or ‘ocular migraines’ usually last about 20 minutes and are followed by a return to normal vision and depending on the person a headache, a migraine, or absolutely no pain.

So, what the heck is going on? It’s not certain but what is believed to happen is that for some reason the blood vessels in the visual cortex (the very back of your brain… about as far from your eyes as you can get and still be in your head) shrink way down and not as much blood is getting through as before. This lack of blood flow means your brain can’t function the way it would like and you start to experience really bizarre things in your vision. It takes your brain, usually, about 20 minutes to figure out this isn’t normal at which point the blood vessels do one of two things. They either return to their normal size, blood flow returns to normal levels and you stop feeling like you ate a brownie you shouldn’t have OR the blood vessels expand to their maximum size stretching themselves to be as big as they can. It’s that extreme stretch that causes the horrible pain people experience with migraines. In some cases the vision changes can last longer than 20 minutes. This usually occurs if someone completely panics causing an adrenaline surge. The resulting stress levels can cause the visual changes to linger for about an hour.

Here’s the real kicker. There’s not much you can do about this. We think that all those blood vessel antics are caused by the same things that cause migraines… so, almost anything (certain smells or foods, weather patterns, stress, lack of sleep. The list goes on and on). Migraine medication can be helpful if a person is getting ocular migraines all the time and it’s seriously interfering with their life but otherwise we just recommend that a person sit back and enjoy the show for 20 minutes. If you’re driving it is strongly recommended to pull over and wait it out. These vision changes are temporary and do not cause any damage to your eyes or your brain.

So rest assured that if you have been properly diagnosed with an ocular migraine your eyes are safe and sound. I would love to leave it at that but there is one more thing. Not all flashes in your eyes are harmless. Retinal holes, tears and detachments can cause symptoms including flashing lights in your vision, floaters and a curtain moving in and out of your vision. These flashes do not go away in 20 minutes and generally are noticed at the very edge of your vision. Retinal detachments are extremely serious and cause permanent loss of vision. If you experience flashing lights in your vision of any kind it is best to have it properly checked by an optometrist. These visits are considered medically necessary and are fully covered by Alberta Health Care. I would advise against taking a risk. If you see flashing let an optometrist have a look at your retina to confirm everything is normal.

For more information feel free to contact us on Twitter, Facebook, Google +, via our website, phone us at (403) 474-6744 or come in anytime. You can also read more at the links below.

All About Vision – Ocular Migraine

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When we are young, the gel inside your eye (the vitreous) is firmly attached to the back of your eye. As we get older, the vitreous gel naturally becomes more liquid and collapses away from the retina. This is called posterior vitreous detachment (PVD). It is very common and more likely to happen as you get older. As the vitreous pulls away from your retina you may see this as a flash of light in one or both eyes, like small sparkles, lightning or fireworks. The flashes tend to be in the extreme corners of your vision and come and go, but don’t obscure any part of your vision. They are different from the shimmering or zig-zag lines that may be part of a migraine. Very occasionally, flashes can be a sign of retinal detachment, which should be treated as soon as possible.

Floaters are small dark or transparent dots or strands or something that looks like a hair or small pieces of a cobweb that float in the vitreous gel inside your eye. They are formed when the vitreous, which is the jelly inside your eye, separates into watery fluid and wavy collagen fibres. They appear to float in front of your eyes and move when you try to look at them. They are very common and are normally harmless.

Who is affected by flashes and floaters?

Flashes and floaters are more common in older people, people who are short-sighted and in people who have had eye surgery.

What are the symptoms of flashes and floaters?

Flashes appear as small sparkles, lightening or fireworks usually in the extreme corners of your vision. They may come and go. Floaters are more visible in bright light, or if you are looking at a plain bright background such as a cloudless sky or white wall.

Usually, the symptoms are nothing to worry about and you can get used to them. However, if you have any of the following symptoms, you should contact your optometrist as soon as possible:

  • a sudden increase in floaters, particularly if you also notice flashing lights
  • a new, large, floater
  • a change in floaters or flashing lights after you have had a direct blow to your eye
  • a shadow or cobweb spreading across the vision of one of your eyes.

If you can’t contact your optometrist you should get urgent attention, ideally from an eye casualty department at the hospital. If you cannot get to an eye casualty you should go to a hospital A&E department.

How do you treat flashes and floaters?

Flashes normally settle down after a few months without treatment. Floaters may be long lasting, but you tend to ignore them after a while. There is usually no treatment required for these conditions.

Watch our video to find out more about flashes and floaters:

Watch our video to find out what it’s like to have floaters:

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