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 cobweb-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 cobweb-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 movable 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 cobweb-like structures very annoying when working at a white computer screen.
Floaters are much like grey hair or wrinkled skin. The eye ages like every 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 a vitreous strand has exerted enough pressure on the retina that a retinal detachment has occurred. If a curtain falls over the vision, it's further proof retinal detachment is present.
A report in the Journal of the American Medical Association states the sudden appearance of floaters and flashes mean 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, can occur without a headache and are believed to be due to migraine.
Retinal detachment is a serious complication and the sooner treatment is started, the greater the chance 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 two per cent of those who have this operation. In 50 per cent 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 per cent 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 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 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 per cent of patients who have never had a cataract develop one within six months of this procedure.
That means 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 to ignore them and "make them your friend."