Floaters & Flashes

Floaters & Flashes – Frequently Asked Questions:

Q: What causes light flashes?

A:  Light flashes are sometimes caused by mechanical stimulation of the retina, often referred to as “pulling”, “forces”, or “traction”.

Q: What can cause this pulling on the retina?

A:  A variety of conditions can cause it, including:

  • Posterior vitreous separation
  • Retinal tears (breaks), and
  • Scarring on the surface of the retina.

Some macular disease patients experience flashes in the central field of vision (straight ahead vision). Patients with successfully repaired retinal tears and detachments may have flashes for several months.

Q: I thought that only retinal breaks cause light flashes. Not true?

A:  Actually, the most common cause of light flashes is the vitreous humor pulling away from the retina. This happens in over 70% of the population as part of the normal aging process, or for other reasons that are not well understood at this time. It is usually accompanied by “floaters”, which represent condensations of the vitreous jelly. By comparison, retinal breaks occur in approximately 6% of the population, and retinal detachments in about 0.06%. Light flashes occur in all three conditions.

Q: Can light flashes be caused by forces not related to the retina of the eye?

A: Yes – Migraines can cause a jagged and flickering area of blocked vision with bright borders.  It typically starts near the center of the vision and progresses to the peripheral vision before disappearing after about 30 minutes. This phenomenon is followed by a headache in only 50% of cases. Although patients describe this as occurring in one eye, in fact it occurs in the corresponding sides of the visual field in both eyes, as can be determined by covering one eye followed by the other when these are occurring.

Migraines are thought to be caused by blood flow disturbances to the visual part of the brain. Blood flow problems can also occur with cervical spine problems, inflammation of the optic nerve, and hardening of the arteries, as well as very low blood pressure. Low blood pressure can cause people to see stars or specks of light, particularly if they change position quickly. An example would be standing quickly from a sitting position or rising quickly after stooping or bending over.

Pregnancy related high blood pressure (pre-eclampsia) can also cause light flashes.

Q: What is a floater?

A: Floaters are relatively transparent, vague, usually curved objects that are seen best when looking at a white piece of paper, blue sky, light colored ceiling, or wall. They sometimes look like cobwebs, worms, rings, dots, or specks. Eye movement makes floaters more visible as they swirl about like seaweed in the ocean surf.

Q: What is the most common cause of floaters?

A: They are usually caused by a clumping of pre-existing vitreous fibers in the eye. Therefore, doctors usually refer to them as vitreous condensations.

Q: What are some of the other causes?

A:  Some floaters are red blood cells or blood clots on the surface of the retina or floating in the vitreous. Such blood cells may occur with some retinal tears but do not necessarily indicate a tear. Occasionally, the vitreous can pull on a blood vessel on the surface of the retina and cause bleeding without causing a tear of the retina. Vascular disorders such as diabetic retinopathy and vein occlusion frequently result in bleeding inside the eye.

Rarely, floaters may be inflammatory in origin. Diseases such as pars planitis and uveitis can cause the formation of clumps of white blood cells (cells that the body produces when there is inflammation).

Floaters can also appear after a YAG laser capsule opening procedure (capsulotomy). After almost 50% of cataract surgery procedures that involve the implantation of intra-ocular lenses, the layer of tissue behind this lens becomes cloudy, causing a decrease in vision. The YAG laser capsule opening procedure is performed in these cases to place an opening in this “lens capsule”, which usually results in better vision, but can also cause floaters.

Q: Can floaters cause total blindness?

A: No – Only a slight blockage of the vision at worst. Floaters are usually not detectable by visual testing unless they are very severe. Importantly, floaters can be related to retinal detachment or a variety of vascular conditions such as diabetic retinopathy, which can result in blindness if not treated.

Q: How common are flashes and floaters?

A: Very common – Over 70% of the population experience these problems.

Q: Are eye strain, nutrition, general health, smoking, or emotional stress related to flashes and floaters?

A: No. There is no known relationship between flashes or floaters and any of these problems.

Q: If one eye develops flashes or floaters will the other develop them as well?

A:  Very likely – In the case of a posterior vitreous separation, it is very common for the same condition to occur in the second eye within a year. For this reason, and because flashes and floaters are sometimes caused by retinal breaks, both eyes should have a dilated fundus exam as soon as possible when flashes or floaters develop in either eye.

Q: What is the treatment for flashes and floaters?

A: If light flashes are due to a posterior vitreous separation and no retinal breaks (tears) are found on careful examination with the pupil dilated, no treatment is necessary. If tears are found by the doctor, laser or occasionally freezing (cryo) treatment is needed. Vitrectomy surgery can be used to remove floaters but is very rarely indicated.

Q: What are the criteria for surgery to remove floaters?

A: Marked persistence of blocked vision may very rarely indicate a need for vitrectomy surgery. The vast majority of patients with floaters do not need vitreous surgery.

If the doctor makes the patient aware of the problem but the patient does not notice any major visual difficulties, surgery is definitely not indicated.

If the problem significantly affects the patient’s ability to work, drive, read, see medicine labels, or other critical activities, surgery may be considered.

The doctor must make certain that there is no other cause of visual loss such as macular degeneration, macular hole, nearsightedness, farsightedness, astigmatism, epimacular membranes, cataract, amblyopia (“lazy eye”), previous retinal detachment, or circulatory problems.

Q: Is there a medication or eye drop for the treatment for flashes or floaters or is surgery the only option?

A: No – There is no medicine, eye drop, vitamin, herb, or diet that is beneficial to patients with flashes or floaters.

Q: Is there a laser treatment for floaters?

A:  No – Only surgery can remove floaters. YAG and other lasers have been used to treat floaters but there is no scientific evidence that laser treatment is effective.

Q: Do floaters ever disappear without surgery?

A: Yes – If the floaters are due to blood cells, they will typically disappear. However, most floaters are condensed vitreous collagen fibers and never completely disappear.

Q: Is the surgery performed on an inpatient or outpatient basis?

A: The surgery is performed on an outpatient basis in all cases, unless there is a medical reason for it to be done in the hospital.

Q: What is the success rate?

A: The surgical success rate for removal of floaters is over 98%

Q: Are there any complications?

A: There can be – There is a significant incidence of cataract progression after vitreous surgery but fortunately this is very treatable.

Retinal detachment can occur after vitreous surgery performed for any reason, including floater removal. Opinions vary widely on the frequency of retinal detachment after floater surgery. Our doctors have an incidence of about 1.5% in the few floater cases that we have done.

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