Flashes and Floaters
Flashes and Floaters
Flashes are sometimes caused by mechanical stimulation of the retina, often referred to as “pulling”, “forces”, or “traction”.
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.
Because flashes and floaters are sometimes caused by retinal breaks, both eyes should have a dilated retinal examination as soon as possible when flashes or floaters develop in either eye.
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.
Q: Symptoms of Flashes
A: 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 many months.
Migraine 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.
Q: I thought that only retinal breaks cause light flashes. Not true?
A: Actually the most common cause 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?
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: Symptoms of Floaters.
A: Floaters are usually not detectable by visual testing unless they are very severe.
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: Can floaters cause total blindness?
A: No, only a slight blockage of the vision at worst.
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: Can light flashes cause total blindness?
A: No, but flashes can be related to retinal tears (breaks) or detachment, which can result in blindness if not treated.
Q: How common are flashes and floaters?
A: Very common. Over 70% of the population experiences these problems.
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. Blood cells in the vitreous 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 sometimes vein occlusion can cause bleeding in the back of 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).
In 5-30% of cataract surgery procedures a thin layer of tissue forms behind the intraocular lens implant causing a decrease in vision. A YAG laser is then used to make an opening in the lens capsule which usually results in better vision, but can also cause floaters.
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.
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 treatment is needed.
A vitrectomy can be used to remove floaters, but is very rarely indicated.
Q: What are the criteria for vitrectomy to remove floaters?
A: Persistent visual disturbance may indicate a need for a vitrectomy. The majority of patients with floaters do not need vitrectomies.
If the doctor makes the patient aware of the problem but the patient does not notice any major visual difficulties, vitrectomy is definitely not indicated.
If the problem significantly affects the patient’s ability to work, drive, read, see medicine labels, or other critical activities, vitrectomy should 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 vitrectomy 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 vitrectomy can remove floaters. YAG and other lasers have been used to treat floaters but there is no scientific evidence that laser treatment is safe or effective.
Q: Do floaters ever disappear without vitrectomy?
A: If the floaters are due to blood cells, they will typically disappear.
Most floaters are condensed vitreous collagen fibers and never completely disappear but they become much less obvious over time.
Q: How long does a vitrectomy take?
A: The procedure takes about twelve minutes. A patch is optional, usually removed the day after surgery. There are no restrictions on activity except no contact sports, skiing, head stands, or diving for two weeks. No air or gas bubble are used. We do not stop anticoagulants prior to surgery.
Q: Is the vitrectomy performed on an inpatient or outpatient basis?
A: The vitrectomy is performed on an outpatient basis in all cases unless there is a medical reason to be in the hospital.
Q: What is the success rate?
A: The success rate for removal of floaters by vitrectomy is virtually 100%.
Q: Are there any complications?
A: There can be: there is a significant incidence of nuclear sclerotic cataract progression after vitrectomy. Some doctors believe that patients with an absolutely clear lens develop cataracts as a result of vitrectomy but our surgeons do not agree. The vast majority of patients over forty already have nuclear sclerotic cataracts (yellowing of the center of the lens), which usually worsens after vitrectomy. Two port vitrectomy or directing infusion fluid near the retina is no longer thought to decrease cataract development. Cataract progression has been shown to be due to depletion of ascorbate in the vitreous and resultant increase in oxygen levels in the vitreous cavity. This cannot be prevented by using a specific technique.
Retinal detachment can occur after vitrectomy and other eye surgery performed for any reason, including floater removal. Opinions vary widely on the frequency of retinal detachment after vitrectomy for removal of floaters but it is 0.5% in our experience.
Q: What technique does Dr Charles use for floater only vitrectomy (FOV)?
A: 25 gauge, sutureless 3-port vitrectomy using the Alcon Constellation Vision System and UltraVit 5000 cut/minute cutter. This approach markedly minimizes both posterior subcapsular cataract development and retinal detachment risk because it minimizes both pulsatile traction on the retina and total fluid throughput. Dr Charles uses local anesthesia and outpatient surgery usually in a surgery center rather than the hospital, and no air or gas bubble.