Diseases

Cataract surgery, especially, if the operation has complications involving the vitreous, increases the risk of a retinal detachment. Cataracts create a cloudiness (opacity) within the lens. In cataract surgery today, the goal is to leave much of the capsule of the natural lens in place. Phacoemulsification, the most common procedure, utilizes a very high speed ultrasonic instrument to break up and suck out the clouded lens material inside the capsule. The new intraocular lens (IOL) is then placed within the capsule. The IOL and intact capsule help to support the vitreous gel which fills the back of the eye. Movement of the vitreous gel is a key factor in retinal detachments because the vitreous movement can place traction on the retina and lead to a hole or tear which can be the start of a detachment. Although cataract surgery does increase the chance of retinal detachment, the risk is low, that is less than 2% over 20 years; and the benefits of cataract surgery ordinarily far outweigh the risk of retinal detachment.Approximately 30% of patients undergoing modern cataract surgery develop opacification of the posterior capsule within a few years following cataract surgery. This clouding of the portion of the natural lens that is left in the eye during surgery can be treated with a laser to open the capsule and let light pass through without being subject to the cloudiness. Patients who undergo this procedure, known as YAG posterior capsulotomy, have a greater risk of retinal detachment than patients who have not undergone YAG laser posterior capsulotomy.

Discomfort, watering, redness, swelling, and itching of the affected eye are all common and may persist for some time after the operation. These symptoms are usually treated with eyedrops. Blurred vision may last for many months, and new glasses may need to be prescribed, because the scleral buckle changes the shape of the eye. The scleral buckle also can cause double vision (diplopia) by affecting one of the muscles that controls the movements of the eye. Other possible complications are elevated pressure in the eye (glaucoma), bleeding into the vitreous -- within the retina -- or behind the retina, clouding of the lens of the eye (cataract), or drooping of the eyelid (ptosis). Additionally, infection can occur around the scleral buckle or even more seriously within the eye (endophthalmitis). Occasionally, the buckle may need to be removed.

Studies have shown that the incidence of retinal detachments caused by tears in the retina is fairly low, affecting approximately one in 10,000 people each year. Many retinal tears do not progress to retinal detachment. Nevertheless, many risk factors for developing retinal detachments are recognized, including certain diseases of the eyes (discussed below), cataract surgery, and trauma to the eye. Retinal detachments can occur at any age but are most common in adults 40 years and older who are highly nearsighted (myopic) and in older people following cataract surgery.

Flashing lights and floaters may be the initial symptoms of a retinal detachment or of a retinal tear that precedes the detachment itself. Anyone who is beginning to experience these symptoms should see an eye doctor (ophthalmologist) for a retinal exam. In the exam, drops are used to dilate the patient's pupils to make a more detailed exam easier. The symptoms of flashing lights and floaters may often be unassociated with a tear or detachment and can merely result from a separation of the vitreous gel from the retina. This condition is called a posterior vitreous detachment (PVD). Although a PVD occurs commonly, in the majority of cases there are no tears associated with the condition.The flashing lights are caused by the vitreous gel pulling on the retina or a looseness of the vitreous, which allows the vitreous gel to bump against the retina. The lights are often described as resembling brief lightning streaks in the outside edges (periphery) of the eye. The floaters are caused by condensations (small solidifications) in the vitreous gel and frequently are described by patients as spots, strands, or little flies. Some patients even want to use a flyswatter to eliminate these pesky floaters. There is no safe treatment to make the floaters disappear. Floaters are usually not associated with tears of the retina.If the patient experiences a shadow or curtain that affects any part of the vision, this can indicate that a retinal tear has progressed to a detached retina. In this situation, one should immediately consult an eye doctor since time can be critical. The goal for the ophthalmologist is to promptly make the diagnosis and treat the retinal tear or detachment before the central macular area of the retina detaches.

The surgical repair of retinal detachments is successful in about 85% of patients with a single vitrectomy or scleral buckle procedure. With additional surgery, over 95% of retinas are reattached successfully. Several months may pass, however, before vision returns to its final level. The final outcome for vision depends on several factors. For example, if the macula was detached, central vision rarely will return to normal due to degenerative changes in the macula. The visual changes in this situation are similar to those seen with the much more common condition known as macular degeneration (age-related macular degeneration or ARMD). Even if the macula was not detached, some vision may still be lost, although most will be regained. New holes, tears, or pulling may develop, leading to new retinal detachments. There may be scarring due to subretinal fibrosis (development of scar tissue beneath the retina). If a gas or air bubble was inserted in the eye during surgery, maintaining proper positioning of the head is also important in determining the final outcome. The use of intraocular gas in phakic eyes (eyes containing the natural lens) is associated with high subsequent incidence of cataract. Close follow-up by an ophthalmologist, therefore, is required and visits will include slit lamp examination and dilated examination of the retina and vitreous. Because of increased risk of retinal detachment in the other eye, dilated examination of the non-operated eye will also be performed. Long-term studies have shown that even after preventive treatment of a retinal hole or tear, 5%-14% of patients may develop new breaks in the retina, which could lead to a retinal detachment. Overall, however, repair of retinal detachments has made great strides in the past 20 years with the restoration of useful vision to many thousands of people.

A retinal detachment is an eye condition involving separation of the retina from its attachments to the underlying tissue within the eye. Most retinal detachments are a result of a retinal break, hole, or tear. Retinal detachments of this type are known as rhegmatogenous retinal detachment. These retinal breaks may occur when the vitreous gel pulls loose or separates from its attachment to the retina, usually in the peripheral parts of the retina. The vitreous is a clear gel that fills two-thirds of the inside of the eye and occupies the space in front of the retina. As the vitreous gel pulls loose, it will sometimes exert traction on the retina, and if the retina is weak, the retina will tear. Most retinal breaks are not a result of injury. Retinal tears are sometimes accompanied by bleeding if a retinal blood vessel is included in the tear. Many people develop separation of the vitreous from the retina as they get older. However, only a small percentage of these vitreous separations result in retinal tears.Once the retina has torn, liquid from the vitreous gel can then pass through the tear and accumulate behind the retina. The buildup of fluid behind the retina is what separates (detaches) the retina from the choroid and retinal pigment epithelium (lining tissue) in the back of the eye. As more of the liquid vitreous collects behind the retina, the extent of the retinal detachment can progress and involve the entire retina, leading to a total retinal detachment. A retinal detachment almost always affects only one eye at a time. The second eye, however, must be checked thoroughly for any signs of predisposing factors or existing retinal tears or holes that may lead to detachment in the future.

The retina is an extremely thin tissue that lines the inside of the back of the eye. When we look around, light from the objects we are trying to see enters the eye. The light image is focused onto the retina by both the cornea and the lens. This light striking the retina causes a complex biochemical change within layers of the retina and this, in turn, stimulates an electrical response within other layers of the retina. Nerve endings within the retina transmit these electrical signals to the brain through the optic nerve. Within specific areas of the brain, this electrical energy is received and processed to allow us both to see and to understand what we are seeing. The retina has been compared to the film of a camera. However, once used, film has a permanent image on it. The retina, in contrast, continually renews itself chemically and electrically, allowing us to see millions of different images every day without them being superimposed.The retina is about the size of a postage stamp. It consists of a central area called the macula and a much larger peripheral area of the retina. The light receptor cells within the retina are of two types, called the rods and the cones. Rods allow us to see in conditions of reduced illumination. Cones provide us with the sharpness of central vision and color vision. The peripheral retina allows us to see objects on either side (peripheral vision) and, therefore, provides the vision needed for a person to move about safely. Since this part of the retina contains a lesser concentration of cones, it does not allow for appreciation of visual detail. Its larger concentration of rods provides better vision during conditions of darkness.In contrast, the macula is a smaller, central area of the retina that contains a high concentration of cones. Accordingly, it enables clear central vision to see fine details for such activities as seeing small objects at a distance, reading or threading a needle. The macula is particularly sensitive to circulatory changes, especially those that occur with aging, such as decreased blood flow. The retina contains a network of branching arteries, which supplies blood that carries the needed oxygen and nutrients to the retina, and a network of accompanying veins, which then carry the blood away together with the waste products of retinal metabolism.

Retinal holes or tears can be treated with laser therapy or cryotherapy (freezing the retina or cryopexy) to prevent their progression to a full-scale detachment. Many factors determine which holes or tears need to be treated. These factors include the type and location of the defects, whether pulling on the retina (traction) or bleeding is involved, and the presence of any of the other risk factors discussed above. Three types of eye surgery are done for actual retinal detachment: vitrectomy, scleral buckling, and pneumatic retinopexy.VitrectomyPars plana vitrectomy (PPV or vitrectomy) is today the most common surgery performed for a retinal detachment. Vitrectomy surgery is performed in the hospital under general or local anesthesia. Small openings are made through the sclera to allow positioning of a fiberoptic light, an irrigation system, a cutting source (specialized scissors), and a delicate forceps. The vitreous gel of the eye is removed to reduce or eliminate the pulling forces of the vitreous (traction) on the retina. Laser or cryotherapy (freezing) is used to treat the retinal tears or holes, and the vitreous is replaced with a gas to refill the eye and reposition the retina. The gas eventually is absorbed and is replaced by the eye's own natural fluid. This procedure may require special positioning of the patient's head (such as looking down) in the postoperative period so that the bubble can rise and better seal the break in the retina. If a gas is used that is absorbed very slowly, the patient may have to walk, eat, and sleep with the head facing down for one to four weeks to achieve the desired result.In the past, vitrectomy was reserved only for certain complicated or severe retinal detachments, such as those that are caused by the growth of abnormal blood vessels on the retina or in the vitreous, as occurs in advanced diabetes; retinal detachments associated with giant retinal tears; vitreous hemorrhage (blood in the vitreous cavity that obscures the surgeon's view of the retina); extensive tractional retinal detachments (pulling from scar tissue); membranes (extra tissue) on the retina; or severe infections in the eye (endophthalmitis).In complex cases today, a scleral buckle (see below) is often also performed together with the vitrectomy. In more complicated cases, a silicone oil maybe placed in the vitreous cavity instead of a gas. This oil must be removed at a later date.Scleral buckle surgeryFor many years, scleral buckling was the standard treatment for detached retinas. It is still used in many cases today. The surgery is done in a hospital operating room with general or local anesthesia. Some patients stay in the hospital overnight (inpatient), while others go home the same day (outpatient). The surgeon identifies the holes or tears either through the operating microscope or a focusing headlight (indirect ophthalmoscope). The hole or tear is then sealed, either with diathermy (an electric current which heats tissue), a cryoprobe (freezing), or a laser. This results in scar tissue later forming around the retinal tear to keep it permanently sealed, so that fluid from the vitreous no longer can pass through and under the retina. A scleral buckle, which is made of silicone, plastic, or sponge, is then sewn to the outer wall of the eye (the sclera). The buckle is like a tight cinch or belt around the eye. This application compresses the eye so that the hole or tear in the retina is pushed against the outer scleral wall of the eye, which has been indented by the buckle. The buckle may be left in place permanently. It usually is not visible because the buckle is located half way around the back of the eye (posteriorly) and is covered by the conjunctiva (the clear outer covering of the eye), which is carefully sewn (sutured) over it. Compressing the eye with the buckle also reduces any possible later pulling (traction) by the vitreous on the retina.A small slit in the sclera allows the surgeon to drain some of the fluid that has passed through and behind the retina. Removal of this fluid allows the retina to flatten in place against the back wall of the eye. A gas or air bubble may be placed into the vitreous cavity to help keep the hole or tear in proper position against the scleral buckle until the scarring has taken place.Pneumatic retinopexyPneumatic retinopexy is usually performed on an outpatient basis under local anesthesia. Again, laser or cryotherapy is used to seal the hole or tear. The surgeon then injects a gas bubble directly inside the vitreous cavity of the eye to push the detached retina against the back outer wall of the eye (sclera). The gas bubble initially expands and then disappears over two to six weeks. Proper positioning of the head in the postoperative time period is crucial for success. Although this treatment is inappropriate for the repair of many retinal detachments, it is simpler and much less costly than scleral buckling. If pneumatic retinopexy is unsuccessful, vitrectomy and/or scleral buckling still can be performed.VitrectomyCertain complicated or severe retinal detachments may require a more complicated operation called a vitrectomy. These detachments include those that are caused by the growth of abnormal blood vessels on the retina or in the vitreous, as occurs in advanced diabetes. Vitrectomy also is used with giant retinal tears, vitreous hemorrhage (blood in the vitreous cavity that obscures the surgeon's view of the retina), extensive tractional retinal detachments (pulling from scar tissue), membranes (extra tissue) on the retina, or severe infections in the eye (endophthalmitis). Vitrectomy surgery is performed in the hospital under general or local anesthesia. Small openings are made through the sclera to allow positioning of a fiberoptic light, a cutting source (specialized scissors), and a delicate forceps. The vitreous gel of the eye is removed and replaced with a gas to refill the eye and reposition the retina. A scleral buckle is often also performed with the vitrectomy. The gas eventually is absorbed and is replaced by the eye's own natural fluid. In more complicated cases, a silicone oil maybe placed in the vitreous cavity instead of a gas. This oil must be removed at a later date.

• Blunt trauma, as from a tennis ball or fist, or a penetrating injury by a sharp object to the eye can lead to a retinal detachment.
• A family history of a detached retina that is non-traumatic in nature seems to indicate a genetic (inherited) tendency for developing retinal detachments.
• In a few patients with a non-traumatic retinal detachment of one eye, a detachment subsequently occurs in the other eye. Accordingly, the second eye of a patient with a retinal detachment must be examined thoroughly and followed closely, both by the patient and the ophthalmologist.
• Diabetes that has been complicated by the development of proliferative diabetic retinopathy can lead to a type of retinal detachment that is caused by pulling on the retina (traction) alone, without a tear. Because of abnormal blood vessels and scar tissue on the retinal surface in some people with diabetic proliferative retinopathy, the retina can be lifted off (detached) from the back of the eye. In addition, the blood vessels may bleed into the vitreous gel. This detachment may involve either the peripheral or central area of the retina.
• Non-rhegmatogenous retinal detachments are those that are not a result of a retinal break, hole, or tear. These include conditions known as exudative retinal detachments and tractional retinal detachments.

Ophthalmologists treat retinal detachment. An ophthalmologist is a medical doctor who is specialized in eye and vision care. Although all ophthalmologists are trained in the diagnosis of retinal detachment, most surgery for retinal detachment is performed by ophthalmologists who have chosen to sub-specialize in vitreoretinal surgery.

• Lattice degeneration of the retina is a type of thinning of the outside edges of the retina, which occurs in 7%-10% of the general population. The lattice degeneration, so-called because the thinned retina resembles the crisscross pattern of a lattice, often contains small holes. Lattice degeneration is more common in people with nearsightedness (myopia). This tendency to lattice degeneration occurs because myopic eyes are larger than normal eyes and, therefore, the peripheral retina is stretched more thinly. Fortunately, only about 1% of patients with lattice degeneration go on to develop a retinal detachment. All patients with lattice degeneration of the retina should be informed about this condition and cautioned about the importance of being seen by an ophthalmologist immediately if they develop sudden floaters, flashes, or a cloud in their vision.
• High myopia (greater than 5 or 6 diopters of nearsightedness) increases the risk of a retinal detachment. In fact, the risk increases to 2.4% as compared to a 0.06% risk for a normal eye at 60 years of age. (Diopters are units of measurement that indicate the power of the lens to focus rays of light.) Cataract surgery or other operations of the eye can further increase this risk in those with high myopia.
• People taking certain kinds of eyedrops have an increased risk of developing a retinal detachment. Pilocarpine, which for many years was a mainstay of therapy for glaucoma, has long been associated with retinal detachment. Moreover, by constricting the pupil, pilocarpine makes the diagnostic exam of the peripheral retina more difficult, possibly leading to a delay in the diagnosis.
• Individuals with chronic inflammation of the eye (uveitis) are at increased risk of developing retinal detachment.

A tear or hole of the retina that leads to a peripheral retinal detachment causes the loss of side (peripheral) vision. Almost all of those affected will progress to a full retinal detachment and loss of all vision if the problem is not repaired. The dark shadow or curtain obscuring a portion of the vision, either from the side, above, or below, almost invariably will advance to the loss of all useful vision. Spontaneous reattachment of the retina is rare.Early diagnosis and repair are urgent since visual improvement is much greater when the retina is repaired before the macula or central area is detached. The surgical repair of a retinal detachment is usually successful in reattaching the retina, although more than one procedure may be necessary. Once the retina is reattached, vision usually improves and then stabilizes. Successful reattachment does not always result in normal vision. The ability to read after successful surgery will depend on whether or not the macula (central part of the retina) was detached, the extent of time that it was detached and whether any scar tissue developed related to the detachment or the surgery.