Floaters, Flashes & Retinal Detachments: Cause and Treatment.

Don't Ignore The Warning Sign of Floaters In Your Eye.

Floaters in the eye and flashes are often the signal of a severe problem, like retinal tears and detachments. This section covers the symptoms and available treatments for a number of conditions relating to retinal detachments. You can click on a topic below, or scroll through the entire section.

What are floaters?
The central cavity of the eye is filled with a gel-like matter called the vitreous humor. Floaters are small clumps of cells, pigment, or gel substance, that "float" inside the vitreous. Floaters may appear as small specks or clouds moving in front of your vision. They are especially apparent when looking at a plain white background, or looking at a brightly illuminated sky. Floaters often appear as if they are floating in front of the eye, and sometimes they imitate a swarm of small insects. In reality, they "float" entirely inside the eye, and typically move when you attempt to focus on them. Floaters are usually quite small and what you're seeing are the shadows cast upon the retina and nerve fiber layer. Floaters that you have been aware of for some time are typically benign; however, a "shower" of new floaters may indicate that you have experienced a new retinal tear, a new vitreous hemorrhage, or a posterior vitreous detachment, or that there is inflammation in the eye (uveitis). A shower of new floaters is your body's way of telling you there is a problem that requires immediate attention.

What is the treatment of floaters?
Typical floaters are not usually treated. If the floaters have been caused by a posterior vitreous detachment without a retinal tear, they will typically "settle" out of the line of vision over several weeks to months. Severe floaters caused by a vitreous hemorrhage that does not clear after several months and prevents useful vision can be removed surgically by a procedure called a pars plana vitrectomy.

What are flashes?
Flashes are the brief sensation of what appears to be bright lights at the edge of your vision. Flashes usually occur all the way to one side, and are more prominent in the dark, or when going from a well-lighted area to a darker area. Flashes usually have no specific shape, but they sometimes have the appearance of lightning bolts. The experience of flashes, especially in conjunction with new floaters, can be an indication of a posterior vitreous detachment, retinal tear, or a retinal detachment. The flashing lights represent the release of an electrical signal from the nerve tissue of the retina; this happens when a vitreous gel pulls on the retina. If the pulling is especially strong, or at the site of a weakness in the retinal tissue, a retinal tear may occur. Any experience of new flashes should be immediately reported to your ophthalmologist, who will usually perform a dilated exam of the retina.

Some flashing light experiences involve seeing a very distinct, often multicolored or fiery jagged line of light, with or without an adjacent black spot. These are called fortification scotomas, and they may start in the center of vision, then spread to the side, or even start at the side. If you carefully close one eye and then the other, you will often notice that the flashes are actually going on in both eyes, but are just more prominent in one or the other. This type of flashing light typically lasts from 5 to 30 minutes, and may or may not be followed by a bad headache. These flashing lights are different from the flashing lights caused by the vitreous tugging on the retina described above, and represent the eye portion of a migraine (with or without a migraine headache). This type of flashing light is usually not serious, but if you are experiencing them for the first time, or you have any doubts, you should contact your ophthalmologist.

How are flashes treated?

If you are experiencing new flashes, it is important to have a dilated eye exam that includes a careful look at the far peripheral edge of the retina. The edge of the retina is thinner than the more central parts, and this is where most retinal tears occur. Your ophthalmologist will often use a device called a scleral depressor to gently indent the side of the eyeball; this brings the peripheral edge of the retina into better view. If no retinal tear or retinal detachment is found, then no treatment is usually needed. However, after the initial exam, it is helpful for you to periodically screen yourself by carefully observing the world around you with one eye at a time. Look for new symptoms such as increased floaters, new or increased flashes or flash intensity, or a shadow. If any of these additional symptoms occur, you need to immediately return to your ophthalmologist for a repeat dilated exam. Also, external laser can sometimes be used to achieve this result, if the view for the laser is sufficient.

What is a posterior vitreous detachment?

The vitreous is the gel-like substance that fills the back of the eye. When you are young, this gel is quite firm and has a uniform consistency; however, as you get older, the gel develops pockets of of looser gel, called liquefaction. Within these pockets, condensations develop that lead to floaters. At some point in most peoples lives, (usually between the ages of 40 and 60, but earlier for moderately to severely near-sighted persons or people who experience a severe trauma to the eye) liquefaction pockets become so numerous that they combine to form larger pockets, then break through the boundary membrane at the back of the eye. When this occurs the membrane of the posterior vitreous separates from the retina at the back of the eye. This is called a posterior vitreous detachment.

The connection between the posterior vitreous gel and the retina is not usually firm, but is more like the attachment of a suction cup to a glass window, or the attachment of the two sides of a new plastic trash bag. The seal is firm, but once a separation begins, all the strength is lost and the separation proceeds in a quick, peeling process. The place where the posterior vitreous is attached to the optic nerve at the back of the eye is usually a point of firm attachment. When this attachment separates, a ring of condensed vitreous gel, which previously had been the site of attachment to the optic nerve, "floats" in the middle cavity of the eye. This ring will often appear as a gray, white or black donut if seen dead on, or as a squiggly line if seen from the side. It is this separation of the vitreous gel from the optic nerve that creates this ring floater, making it the hallmark of a complete posterior vitreous detachment. The detachment usually goes smoothly, and does not present a problem or danger to vision. However, sometimes the vitreous sticks more firmly at the edge of the retina and tugs while it is being peeled off. This tugging is the cause of flashes, and if the tugging is strong enough, a retinal tear may develop. A retinal tear often tears a retinal blood vessel as well, and the blood from the torn vessel leads to the shower of new floaters.

How is a posterior vitreous detachment treated?
An old posterior vitreous detachment, or a new posterior vitreous detachment that is not associated with any retinal tear or retinal detachment requires no treatment. New floaters associated with a new posterior vitreous detachment typically resolve over several weeks to months, and are not harmful even if they don't go completely away. However, if a patient with a recent posterior vitreous detachment also has a retinal tear or retinal detachment, then these require urgent treatment.

What is a retinal tear?
A retinal tear is exactly what it sounds like: a tear in the nerve tissue of the retina. Retinal tears typically occur at the thin edge of the retina. Tears usually take two forms triangular horseshoe tears and circular tears that often has a small divot of retina floating over the circle.

How are retinal tears treated?
New tears, or any tear associated with sudden new flashes and/or floaters requires prompt treatment. Treating a retinal tear involves creating a firm adhesion, called a retinopexy, between the retina and the wall of the eye. This is usually done by creating a circle of small scars around the tear with a laser. If the view of the retina is poor, like when it is blocked by a dense cataract or blood in the vitreous cavity, the adhesion is created by using a metal probe cooled to -20° C, called a cryoprobe. The cryoprobe is placed against the wall of the eye, underneath the tear, where local inflammation caused by the freezing creates the adhesion. A similar process using a transcleral diode laser can also achieve the same result.

What is a retinal detachment?
A retinal detachment is a separation of the retina's nerve tissue from the wall of the eye. When this separation occurs, the nerve tissue cells are isolated from their supplies of nourishment, so they deteriorate and eventually die. This can cause permanent loss of vision in the affected eye, so it is imperative that a retinal detachment be quickly repaired. The most common type of retinal detachment is called a rhegmatogenous retinal detachment. Rhegmatogenous retinal detachments occur when fluid from the vitreous cavity flows through a retinal tear and moves underneath the retina, raising it up off the wall of the eye. Like the posterior vitreous, the retina is only firmly attached to the wall of the eye at the optic nerve, at the far peripheral edge of the retina. The rest of the retina is attached to the wall of the eye in a fashion similar to a suction cup. Once a small amount of fluid gets underneath the retina, the "seal" is broken and the damaging fluid can spread rapidly.

The initial symptoms of a retinal detachment are the same as a retinal tear or a posterior vitreous detachment, such as flashes and floaters; however, as the detachment progresses, a dark, opaque moon-shaped shadow or curtain will appear on one side of your vision. This curtain, which is sometimes seen to billow like a sail in the wind, is actually the detached retina tissue floating in the vitreous cavity.

Retinal detachments can be divided into two separate levels of severity: "macula on" (the macula is the back portion of the retina) and the more critical macula off. Since retinal detachments tend to start in the periphery as macula on, and only later progress to macula off, the prognosis for the return of normal vision after the repair of a macula on detachment is better. Macula off detachments that are less than a week old tend to have a better visual prognosis than older macula off retinal detachments. See an ophthalmologist immediately upon the earliest detection of the suspicious symptoms outlined above. With modern surgical techniques, over 90% of all retinal detachments can be successfully repaired, frequently on an outpatient surgery basis and sometimes even in the office.

There are two other types of retinal detachments besides rhegmatogenous. The first is called a traction retinal detachment. Traction retinal detachments occur when scar tissue contracts and pulls the retina off its attachment to the eye wall. Traction retinal detachments are most common in diabetics who suffer from severe diabetic retinopathy, but also occur in eyes with traumatic injuries and eyes that have previous failed retinal detachment repair. The second is called a serous retinal detachment. Serous, or exudative, retinal detachments happen when fluid collects in the normally closed space between the retina and the wall of the eye. Unlike a rhegmatogenous retinal detachment, the fluid does not come through a tear in the retinal tissue, but is made within the tissue itself. The typical cause of a serous retinal detachment fluid produced from an inflammatory condition in the choroidal layer of the eye, uveitis, or from a tumor in the choroid of the eye such as an ocular melanoma. The small "blisters" of fluid which develop during the active phase of central serous chorioretinopathy, are actually small serous retinal detachments.

How are retinal detachments repaired?
Most retinal detachments are emergencies which require urgent surgical repair. The object of any retinal detachment repair is to get rid of the fluid underneath the retina and allow the retina to lay "flat" upon the concave contour of the wall of the eye. There are several ways to do this, each outlined in the sections below. Since the vast majority of retinal detachments are of the rhegmatogenous type, we'll focus on this type of repair. We'll also discuss traction and serous retinal detachments.

Scleral buckle to repair retinal detachment
A scleral buckle is made of a piece of silicone (solid or sponge) which is sewn to the outer wall of the eye, called the sclera. The scleral buckle was developed in the early 1960's, and was the first effective treatment for repairing retinal detachments. Scleral buckles are still used today, either alone or in conjunction with other methods. Here's how it works: the scleral buckle indents the wall of the eye toward the detached retina. This indentation makes the liquefied vitreous unable to pass through the retinal tear. Once the hole is closed, the fluid is absorbed by the natural mechanisms of the eye. Sometimes, if there is quite a bit of fluid under the retina, the retinal surgeon may drain the fluid under the retina by making a small incision through the wall of the eye. Because of the risk of bleeding when the wall of the eye is incised, this external drainage is not done by many surgeons. Once the fluid under the retina is gone, a permanent seal is made around the retinal tear with a cryoprobe or laser.

Vitrectomy for the repair of retinal detachments
Vitrectomy is a sophisticated technique of operating on the retina from inside the eye. During a vitrectomy, small incisions are made in the wall of the eye, through which various instruments are passed. Typically, there are three incisions. One is for the infusion of fluid into the eye. A second is for the insertion of a fiberoptic light source. A third is for the insertion of a working instrument such as a microscissor, forceps, knife, or vitrector. The primary surgical tool, the vitrector is used to remove the sticky vitreous gel that is causing undue traction upon the fragile retinal tissue. Vitrectomy techniques have advanced rapidly over the past 20 years, allowing for more complex retinal problems to be addressed with increasing safety. New developments in vitrectomy techniques include:

  • The use of picks and forceps attached to the end of the fiberoptic light source, allowing for a controlled two-handed approach to the dissection of delicate tissues.
  • The use of sophisticated wide-angle optics, which allow the surgeon to see nearly the entire posterior cavity of the eye in one visual field.
  • The use of long acting gases and silicone oil for internal tamponade of retinal pathology.
  • The use of heavy liquids to gently manipulate the retinal tissue and to displace subretinal fluid.
  • Smaller gauge surgery for less invasive operations that allow for quicker healing times

Office-based repair of retinal detachments
In addition to the outpatient hospital techniques described above, many uncomplicated retinal detachment procedures can be done in a doctor's office. Two of these procedures, pneumatic retinopexy and temporary Lincoff balloon buckle,have been shown to have the same or nearly the same success rate as traditional hospital-based surgery. What's more, if the office-based repair is unsuccessful, no ground is lost if a second procedure needs to be performed.

Pneumatic retinopexy for the repair of retinal detachments
In a pneumatic retinopexy, a long-acting gas is injected into the eye to create an internal tamponade of the retinal tear. These gases stay in the eye for 1 to 3 weeks, during which time they slowly dissipate, and eventually disappear. With the tear in the retina closed by this "air-lock", the fluid underneath the retina gets absorbed in a few days. A cryoprobe or the laser creates the adhesion that keeps the tear closed once the gas has disappeared. A pneumatic retinopexy is less invasive than hospital-based retinal detachment repairs, and allows for a faster recovery. While the gas is in the eye, it rises like a helium balloon. In order to keep the air lock over the retinal tear, it is important for the patient to hold his or her head in the proper position for 1 to 2 weeks, usually face-down. In addition, while the gas is in the eye, the patient is unable to travel in an airplane because a sudden depressurization of the cabin could lead to dangerous expansion of the gas bubble inside the eye. These inconveniences aside, a pneumatic retinopexy in the office is usually preferable to hospital-based surgery.

Temporary Lincoff balloon buckle for repair of retinal detachments
The Lincoff balloon works the same way as a scleral buckle, except there are no sutures, and the temporary balloon buckle is removed after a week. The tip of the balloon is inserted into the eye, then inflated with a small amount of sterile saline. On one side, the balloon indents the eye in the same way as a scleral buckle. On the other side, the balloon presses against the bony orbit, holding it in place. The balloon is attached to a 4-inch long thin tube that is taped to the patient's forehead for one week. A cryoprobe or laser creates the adhesion that keeps the tear closed once the balloon is removed. One advantage that the balloon has over a pneumatic retinopexy is that retinal tears below the equator of the eye can be treated without resorting to uncomfortable positioning. For example, a retinal detachment caused by a retinal tear at "6 o'clock" in the back of the eye can be treated easily with a balloon. A pneumatic retinopexy would require the patient to hang his or her head upside down for a minimum of one week, an impossible task.

Repair of non-rhegmatogenous retinal detachments
Tractional detachments are caused by fibrous scar tissue that pulls the retina off the wall of the eye. Tractional detachments, like those that occur in diabetic retinopathy, are best treated with modern vitrectomy techniques that carefully dissect, peel, and/or remove the scar tissue. Sometimes a scleral buckle is also needed to create slack in the tractional bands by indenting the wall of the eye inwards. Scleral buckles are also used when a tractional band pulls so hard that the retina is torn, creating a combined tractional and rhegmatogenous retinal detachment.

Serious (exudative) detachments are treated by targeting the underlying cause of the fluid that is elevating the retina. In the case of an inflammatory condition, medicines such as steroids can be used to reduce the fluid. In the case of a tumor, laser and/or radiation is often used to attack the tumor, shrink it, and reduce the fluid produced by the tumor.