People who tend to party too much on a Saturday night are apt to see pink elephants in their vision. But others who never misbehave may suddenly notice spots, threads or cob-web-like structures floating in front of their eyes. What causes these images and when are they a medical emergency?
Eye floaters are those tiny flecks, spots or cob-web-like structures that appear to drift aimlessly around in your field of vision. A few people find them terribly annoying. Others fret that they may herald the onset of a serious eye problem. Or even end in blindness.
What causes these floaters? The vitreous is a large chamber in the back part of the eye. Early in life it consists of a gel-like substance that is crystal clear. But as we age, this mass begins to dissolve and become liquefied. This causes some undissolved particles to float around in the more liquid vitreous. These moveable objects then cast shadows on the retina and sufferers see them in front of their eyes.
Patients become particularly aware of floaters when they look at a white wall, or on a bright sunny day, or when they gaze at the sky. Others find the cob-web-like- structures very annoying when working at a white computer screen.
Floaters are much like gray hair or wrinkled skin. The eye ages like any other organ in the body. But each part of the eye gets its wrinkles in a different way. For instance, the need to back away to see letters in the telephone book is the result of the lens becoming more rigid with age.
Some people become compulsive about floaters and can’t stop looking at them. They’re frustrated that these specks never stand still when they try to focus on them. And of course the more they search for floaters, the more they find, and the more it bothers them. In fact, a large number of people have floaters but never see them.
Dr. Charles L Schepens, one of Harvard’s famous ophthalmologists, often gave this sage advice to patients troubled by floaters. “Make them your friend,” he said. But there are times when unfriendly floaters appear.
Patients who see a sudden shower of floaters, sometimes associated with flashes of light or sparks, should immediately seek medical attention. This may indicate that a vitreous strand has exerted enough pressure on the retina that a retinal detachment has occurred. And if a curtain falls over the vision, it’s further proof that retinal detachment is present.
A report in the Journal of the American Medical Association states that the sudden appearance of floaters and flashes means that one in seven people with these symptoms will have developed either a tear or detachment of the retina.
But not all flashes are of retinal origin. Some people complain of seeing flashes of light that appear as jagged vibrating lines or “heat waves” in both eyes. These sensations usually last about 10 to 15 minutes and can occur without a headache and are believed due to migraine.
Retinal detachment is a serious complication and the sooner treatment is started, the greater the chance that vision can be restored. It’s a terrible tragedy when people ignore a sudden appearance of floaters hoping they will go away and lose an eye that could be saved.
Some people are more prone to retinal detachment. For instance, people who are near-sighted are more likely to develop this problem. Diabetics are also more susceptible to another type of detachment caused by scar tissue.
Retinal detachment is also a complication of cataract surgery. The problem occurs in up to 2% of those who have this operation. And in 50% of cases this complication follows within a year of surgery. Improvement in vision may take weeks or months depending on the severity of the detachment. But fortunately the retina can be reattached in 95% of cases.
Several procedures are available to treat retinal detachments. Retinal surgeons often use laser therapy and cryosurgery (intense cold) to seal the tear and reattach the retina.
Another procedure called pneumatic retinopexy can be performed. This involves injecting a gas bubble into the eye and placing it over the tear. This blocks further release of fluid and allows fluid underneath the retina to be absorbed.
Scleral buckling is the time-honoured procedure. The detachment is first treated with cryosurgery. Then a soft silicone band is placed around the eyeball. This helps to bring the retina closer to the back part of the eye and promotes healing.
Some patients with major problems are treated by vitrectomy. In this procedure the vitreous is removed to stop it from tugging on the retina. The vitreous is then replaced with air or gas. Over a period of time the air or gas is replaced by the body’s own fluid.
Vitrectomy is normally used as a last resort, in part because 80% of patients who have never had a cataract develop one within six months of this procedure.
This means that this procedure is never a prudent option for those who are simply annoyed by constantly seeing floaters. The risk of complications is too great. The best treatment is to try and ignore them and “make them your friend”.
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