Floaters, Flashes, and Halos
Chat Highlights
June 7, 2006

On Wednesday, June 7, 2006, Dr. Elliot Werner, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Floaters, Flashes, and Halos."

Moderator:  Welcome back to chat, Dr. Werner. Tonight the topic is "Floaters, Flashes, and Halos."

Dr. Elliot Werner:   Let me start by giving you a definition of floaters and flashes.  A floater is something in the fluids of the eye that casts a shadow on the retina and looks like a dark spot or spots floating around in the field of vision.  Floaters can only be seen with the eyes open and in a lighted environment.

Flashes can be seen even in the dark or sometimes with the eyes closed.  Flashers are flashes of light or bright objects that appear in the field of vision.

P:   What causes floaters?  Are they white, black, or gray or do they vary?

Dr. Elliot Werner:  Floaters are rarely white.  They are usually gray or black, since they are actually shadows on the retina.  Anything, such as blood, cells, pieces of protein, etc., that gets into the vitreous fluid can cause a floater.   Many different eye conditions have floaters associated with them.

P:  What are those conditions?

Dr. Elliot Werner:  The most common cause of floaters in middle-aged and older persons is something called a posterior vitreous detachment (PVD).  That is an annoying condition but rarely serious.  Bleeding, inflammation in the eyes, and myopia are other causes of floaters.

P:  What is vitreous?

Dr. Elliot Werner:  Vitreous is the jelly-like fluid that fills most of the inside of the eyeball. Normal vitreous has the consistency of Jell-O and is completely transparent.

P:  How does myopia cause floaters?

Dr. Elliot Werner:  Myopia is associated with a type of vitreous degeneration that produces floaters.

P:  Are floaters a serious problem?

Dr. Elliot Werner:  Sometimes yes, sometimes no. It depends on the cause.  The patient usually cannot determine whether or not it's serious, especially if floaters begin suddenly.  That requires a specific diagnosis by an ophthalmologist.

P:  Are people with glaucoma more prone to floaters?  I have a ton of them.

Dr. Elliot Werner:  Probably not.  Glaucoma does not affect the vitreous fluid and does not cause floaters.

P:  A doctor discovered my intraocular pressure (IOP) was high when I suddenly started seeing floaters.  I assumed the floaters were associated with glaucoma.

Dr. Elliot Werner:  That was probably a coincidence.

P:  I haven't seen a floater in several years.  Don't they increase with age?

Dr. Elliot Werner:  They may or may not.  Very often people with floaters from vitreous detachment report that the floaters become much less prominent as time goes by.

P:  I see many floaters just before and during menstruation.  I also get them with eye pain. Is there any correlation?

Dr. Elliot Werner:  I haven't heard that before.  Pain with floaters (or more often, flashes) is frequently due to a migraine.

P:  An eye surgeon of some sort (a Russian now living in the U.S., I believe) claims success in dissolving floaters using a laser procedure. Is research being done about that procedure?

Dr. Elliot Werner:  I don't know of any such research being done in the U.S. Some people have claimed to relieve certain types of floaters with laser, but it is not commonly done.  The people in the U.S. and Western Europe who have tried it have not reported good, consistent results.

P:  Do any of the glaucoma surgeries increase the risk of floaters?

Dr. Elliot Werner:  Not directly, but bleeding in the eye is an occasional complication of glaucoma surgery and that may produce floaters.  A sudden decrease in the eye pressure can alter the configuration of the vitreous, which can produce floaters.

P:  Is a flash something to be concerned about?

Dr. Elliot Werner:  As with floaters, that depends on the cause.  A solitary flash without any loss of vision is rarely serious.  Persistent flashes, especially if there is some change in the eyesight, are potentially serious signs of retinal detachment.

P:  Does a vitrectomy, permanent removal of the vitreous, eliminate floaters?  I have had vitrectomies in both eyes and still see floaters sometimes.

Dr. Elliot Werner:  Vitrectomy will usually relieve floaters, but patients after vitrectomy may develop new floaters.

P:  What is used to replace the vitreous?

Dr. Elliot Werner:  The vitreous removed during a vitrectomy is replaced with salt water.

P:  Sometimes when I have my eyes closed, a dull light will slowly appear and then disappear in a continuous pattern. Is that light flashes?

Dr. Elliot Werner:  No, that is actually a normal response of the visual system to closing the eyes.  Even in a completely pitch-dark environment, the retina produces nerve impulses that appear as light.  Flashes are just that: bright spots or streaks of light that seem to go on and off rapidly.

P:  'Flash' implies something of brief duration.  What's the name for similar but apparently permanent bright or glowing objects?

Dr. Elliot Werner:  Photopsia.  [Editor's note:  "Photopsia is the presence of perceived flashes of light. It is most commonly associated with posterior vitreous detachment, migraine with aura, migraine aura without headache and retinal break or detachment."

http://en.wikipedia.org/wiki/Help:Contents]

P:  Does the presence of many heavy floaters skew the results of visual field tests?

Dr. Elliot Werner:  That depends upon what is causing them.  Blood in the vitreous can certainly affect the visual field.  The usual types of floaters seen in most people do not seem to affect the results of visual field tests.

P:  I went through a period of seeing flashes when I turned my head.  A retina specialist said nothing was wrong; it was just that the vitreous was very thick and was pulling on the retina when I turned my head suddenly.  It hasn't happened in a long time.  How common is it for the vitreous to fluctuate in viscosity and is the reason known?

Dr. Elliot Werner:  The vitreous becomes less viscous and more fluid with age.  What you describe is called phosphenes of rapid eye movement and is a normal occurrence.  It is what accounts for "seeing stars" when we get hit in the head.

P:  Can laser surgery bring on flashes?  I ask because a close friend had laser surgery for narrow-angle glaucoma in April and May and weeks later began to see flashes.

Dr. Elliot Werner:  Laser iridectomy can cause flashes due to the light that sometimes gets into the eye through the iridectomy opening.  The development of a vitreous detachment after an iridectomy is probably a coincidence, but could be due to the pilocarpine put in the eye before the iridectomy was performed.

P:  What research, if any, is being done currently to eliminate floaters? Can you tell us of anything that's promising?

Dr. Elliot Werner:  Again, it depends on the cause of the floaters.  The usual types of benign floaters are normal aging changes.  While they can be a nuisance, they are not dangerous and, to my knowledge, no one is doing research specifically to stop the aging process in the vitreous.

Moderator: What are the halos many of us see?

Dr. Elliot Werner:  A halo is a ring seen around a bright light source, such as a headlight or light bulb. Halos can be either white or rainbow colored, depending on the cause.

P:  Are halos any indication of low or high IOP?

Dr. Elliot Werner:  Neither.  Halos indicate something in the transparent structures of the eye that is interfering with the transmission of light back to the retina.  The most common causes of halos are corneal edema (swelling), cataract, and high humidity in the air.

P:  As a result of ICE (iridocorneal endothelial syndrome), I have a permanent, colored halo in the affected eye. Is the halo caused by corneal edema?

Dr. Elliot Werner:  Probably.  Corneal edema typically produces colored halos.

P:  Does corneal edema mean that the cornea is failing?

Dr. Elliot Werner:  It means the cornea is swollen with fluid.  Corneal edema has many causes, including failure, but not always.

P:  Are halos an indication of something wrong?  When my IOP is increasing, I see halos around lights, especially street lights at night.

Dr. Elliot Werner:  Halos usually indicate something wrong.  If you see halos when your IOP is high, you are probably developing corneal edema at those times.

P:  Can dry eyes cause halos?

Dr. Elliot Werner:  Yes, because of the irregularity of the corneal surface that develops in patients with dry eyes.

P:  Do halos have a well-defined edge or do they look spiky?

Dr. Elliot Werner:  That varies a lot with the patient.  I've heard all varieties described.

P:  For months now, once the lights are dimmed, I've seen a long-lasting glowing area in the same area as my scotoma, but more extensive.  Is it likely that this is caused by glaucoma?

Dr. Elliot Werner:  Probably it is the result of the response of the abnormal area of retina and optic nerve to the light and contrast.

P:  Can tinting of prescription lens, refractions, etc. cause halos?  I ask because I always used to see halos at night when wearing a pair of tinted glasses.  When I removed them, the halo disappeared.

Dr. Elliot Werner:  Probably.  I know that dirt or scratches on the glasses can cause halos.

P:  Fifteen days after cataract surgery in November 2002, I suddenly developed cloudy, hazy vision.  My surgeon said it was PVD.  Every year it got worse.  I understand that I have a lot of pigment in the vitreous.  What is the prognosis for PVD and a lot of pigment in the vitreous?

Dr. Elliot Werner:  Posterior vitreous detachment usually develops suddenly and often occurs right after cataract surgery because of the sudden changes in the eye pressure and fluid during the operation.  Pigment often gets into the vitreous during a PVD.  PVD rarely affects vision per se, but the floaters can be very annoying.  They usually get better with time.

P:  Is the new suture-less vitrectomy, 23 or 25 gauge, safer than 20 gauge, principally considering the possibility of a retinal detachment?

Dr. Elliot Werner:  My retina colleagues tell me that the smaller gauge vitrectomy instruments are safer and provide a better level of control.  They are not, however, effective in all situations and are somewhat slower.

P:  I had a trabeculectomy in my right eye last March.  My IOP is 17 mm Hg and my visual field shows no progression of my glaucoma.  However, I have a sensation in that eye, which is like a weak flash and I feel a pulsing sensation.  Is that normal and will it stop after a while?

Dr. Elliot Werner:  That is not unusual.  Most patients get better as time goes on.

P:  Why do I see floaters more on sunny days?

Dr. Elliot Werner:  The perception of floaters is due to the shadow they cast on the retina, so naturally you will see them more in bright light because they make a darker shadow.

P:  When the lights are turned out, or when I close my eyes, the area of my scotoma is lighter than the darkness.  If a scotoma is a sightless area, how could that be?

Dr. Elliot Werner:  Light does something called bleaching the retina, so when you turn the lights off suddenly, the bleached retina does not see very well for a while, until it adapts to the darker environment.  The area of the scotoma does not respond to light, so it does not bleach.  That part of the field of vision may appear lighter for a few moments, until the rest of the retina catches up.

P:  What about seeing halos when looking at the sun occasionally or seeing concentric circles in rainbow colors?

Dr. Elliot Werner:  Watching the sun is quite dangerous and should not be done. Most halos seen around the sun are due to the atmosphere.

P:  I don't look directly at the sun and I protect my eyes with sunglasses.

Dr. Elliot Werner:  You need very dark sunglasses that filter out all the ultraviolet and infrared.

P:  Could taking medicine like steroids or glaucoma medication cause floaters, flashes, or halos?

Dr. Elliot Werner:  Steroids by themselves would not cause flashes, floaters, or halos, but complications of steroid use, such as cataracts, might.

P:  After a trabeculectomy in my right eye, for about two months I saw a mark when I closed my eyes or turned out the lights. Was that caused by the hole created by the laser?

Dr. Elliot Werner:  That probably was due to the extra light entering the eye through the iridectomy.

Moderator: What is the difference between vitreous detachment and retina detachment?

Dr. Elliot Werner:  In vitreous detachment, the vitreous tears away from its attachment to the area around the optic nerve and separates into liquid and solid fractions.  It is almost always a benign and harmless condition that occurs in almost everybody with age.

Retinal detachment means the retina has torn away from the back of the eye, like wallpaper peeling off a wall.  Retinal detachment is a serious condition.  Unless it is promptly repaired with surgery, a retinal detachment can lead to irreversible blindness.

P:  What is the take-home message for people who see a floater, flash, or halo for the first time?

Dr. Elliot Werner:  If it goes away and doesn't come back, don't worry.  If there is any loss or significant change in the vision, get to an ophthalmologist immediately.  If there is no change in vision, but the problem doesn't go away in a day or so, see the ophthalmologist.

Moderator: Thank you so much, Dr. Elliot, for discussing this topic.

Dr. Elliot Werner:  I wish you all a great summer.  Wear sunscreen, sunglasses, and a hat in the sun.

On June 14, Dr. Wilson discussed "Late Bleb Leaks in the Chat room. Click here for highlights of that meeting.

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