Patient Education
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Patient Education Resources New Patient Information LOW VISION DEVICES Early Detection and Treatment of Neovascular Age-related
Macular Degeneration
Neil M. Bressler, MD To Print: Click your brower's PRINT button. NOTE: To view the article
with Web enhancements, go to:
http://www.medscape.com/viewarticle/432579
Common Office & Surgical Procedures
Today’s treatment for macular holes Advances in surgical techniques improve vision Macular holes were once considered an untreatable problem; however, because of advances in retinal surgery, many patients can be helped. It is possible for anyone to develop a macular hole, but they are most common among women about 60-70 years of age. Macular holes may occur for a variety of reasons, but are usually a result of traction from the vitreous gel on the macula. Since the macula is responsible for central vision, this problem causes severe and often complete loss of central vision. Fortunately, we’ve come to understand this problem better than ever before and can even restore vision in many cases with surgery. The extent of the patient’s recovery is dependent on several factors such as the severity of the hole, time since onset, and other variables. Sometimes the hole spontaneously resolves, although it is much more common to require surgery. The operation is performed with local anesthesia under a microscope. During the procedure, the doctor injects a gas bubble inside the eye. The purpose of the gas bubble is to place gentle pressure on the retina and help seal the hole. The biggest challenge of macular hole repair is to maintain the proper head position afterward. Since gas rises, the patient must be able to keep his or her head down so the bubble floats up and presses on the back of the eye. This is very critical for approximately two weeks following the surgery. There are many creative ways to stay in the correct position and remain comfortable. The body slowly absorbs the gas bubble over approximately three months. In some cases, the eye is filled with silicone oil instead of gas. This is easier for the patient because no special positioning is necessary; however, the oil must be removed with a second operation several months later. With the surgical treatments available today, we are able to restore partial vision in 70-90% of our patients. Most patients find that their vision improves approximately two lines better on the eye chart. As retinal surgeons, we are encouraged by the advances made in the field of macular surgery. New treatments are being developed all the time as we continue to learn about this incredibly complex sensory tissue. Macular Hole The human eye is shaped like a ball, measuring approximately one inch across, and functions like a living camera. The front portion of the eye, consisting of the cornea (the clear cover of the eye), the lens and the iris (the colored portion of the eye), acts to focus light on the back of the eye, much like the lens and aperture system of a camera focuses light on a piece of film. The retina, similar to the photographic film itself, is a thin layer of tissue that lies against the back surface of the eye wall. The image obtained by the retina is transmitted via the optic nerve to the brain and forms the picture that we see. Unlike a camera, the image obtained by the retina is not of uniform clarity or sharpness. Only the central portion of the retina, the macula, is sensitive enough to provide high quality vision for tasks such as reading, watching television, or driving. The macula is a very small area, with the central portion being only about the size of the head of a pin. It is only this specialized area of the retina, the macula, that is capable of the detailed vision necessary for many daily tasks. In order to maintain its round structure, the central portion of the eye is filled with a jelly-like substance known as the vitreous. At birth and through early years, the vitreous has a fairly solid structure, having a consistency somewhat between Jell-O and molasses. As a person ages, however, the vitreous jell begins to shrink and becomes more condensed toward the front part of the eye, being replaced by liquid as the process continues. As the vitreous shrinks, it pulls away from the surface of the retina. In most cases, this pulling away or vitreous separation occurs without any negative effect. A patient may notice floaters but no significant visual damage occurs. In some individuals, however, there may be an area where the vitreous is firmly attached to the surface of the retina. As the shrinkage and forward movement of the vitreous progresses, traction or pulling can be exerted on the retina, and eventually a small hole may form. If the hole occurs in the outer or peripheral portion of the retina, a retinal tear or detachment may result. If, on the other hand, the vitreous is firmly attached to the central portion of the retina (the macula) then shrinkage and movement of the vitreous can result in the formation of a hole in this region, known as a macular hole. The fluid which has replaced the vitreous jell in many areas may then seep through the hole, causing a localized separation of the retina centrally. This process results in a defect or dark spot in the central vision with distortion and central vision loss resulting. Clinical photo of a macular hole Symptoms of a macular hole are common to most conditions affecting the central part of the retina. They include: decreased central vision for both distance and reading activities, distortion in central vision, a small defect in the central vision where small letters may disappear. The diagnosis of a macular hole is made when an ophthalmologist performs a dilated retinal examination and examines the back of the eye. A fluorescein angiogram (injection of a dye into the vein with photographs taken of the back of the eye) may be recommended to evaluate the situation and ensure that the macular hole is due to the vitreous traction as described above, and not secondary to other rare conditions in the back of the eye. Until recently, very little could be done to correct the visual deficit resulting from macular holes. As a result of the introduction of microsurgical techniques, it is now possible to offer a surgical procedure with the potential for some visual improvement. This procedure is known as a vitrectomy, and involves the microscopic removal of the vitreous jell within the center of the eye. Particular attention is paid to removing any of the vitreous attachments from the macula, thus releasing the traction or pulling on the retina which caused the macular hole initially. This permits settling of the retina against the wall of the eye. In order to completely close the macular hole, however, additional pressure must be exerted on this portion of the retina to allow for complete healing to take place. To assist in this process, a large air bubble is placed within the eye, which, when it comes into contact with the retina, presses it against the wall of the eye, sealing the macular hole. This process acts much like a hand holding wall paper against the wall permitting it to stick and remain in position as the "wallpaper glue" dries. In order to have its maximal effect, the air bubble must apply continued upward pressure against the retinal surface in the area of the macula. Because the macula is located in the back part of the eye, a patient’s head must remain in a "face-down" orientation to allow the air bubble to rise toward the back of the eye and exert this pressure. Patients must maintain this face-down position for approximately 2-3 weeks after surgery in order to achieve successful closure of the macular hole and maximize the chances for vision improvement. This face-down positioning is the single most critical portion of the procedure for closing macular holes. As a result, emphasis must be placed on the patient’s ability to cooperate with strict face-down positioning at all times for a period of approximately three weeks after surgery in order to achieve successful outcome. In order to increase the patient’s ability to comply with these instructions, numerous devices have been developed that assist the patient in maintaining this face-down position throughout the day and at night as well. Devices can be purchased or rented from a variety of companies that permit more comfortable positioning during sleep as well as allowing the patient to maintain a face-down position while eating and reading. At the end of the 2-3 week period of strict face-down positioning, the patient is then permitted to resume a more normal upright posture. The air bubble itself, however, may take anywhere from 6-8 weeks following surgery to completely disappear. The air bubble is gradually resorbed by the body, and the vitreous cavity is then filled with liquid produced by cells in the front of the eye. The surgical procedure itself is performed typically under local anesthesia, and a patient may remain in the hospital overnight, or may be scheduled for ambulatory surgery, able to return home by the end of the day of the surgical procedure itself. A postoperative examination within 24 hours of surgery is required in all cases. Regular follow-up examinations are performed during the first three weeks of recovery, to monitor for successful closure of the hole, observe for any potential complications, and to reinforce the importance of face-down positioning. Patients typically utilize several eye drops applied to the operated eye over the course of several weeks following the surgical procedure. Approximately 6-8 weeks after surgery, when the bubble has completely resorbed, the patient is measured for glasses. Full visual recovery may not occur until as late as three months after the surgical procedure. As with all surgical procedures, there are potential complications or side-effects associated with the repair of the macula hole. These include a small percentage of patients who develop retinal tears or detachments during the surgical procedure itself, or in the immediate postoperative period. These problems are usually easily repairable. In patients who have not already undergone cataract surgery, the development of a cataract occurs in almost all individuals within six months to two years. Surgical removal of the cataract and placement of an intraocular lens is then required. Frequently asked questions Is a macular hole the same as macular degeneration? No, macular holes and macular degeneration are two separate and distinct conditions. As described elsewhere on this website, macular degeneration is a condition affecting the tissues lying under the retina, while a macular hole involves damage from within the eye, at the junction between the vitreous and the retina itself. There is no relationship between the two diseases. Is this is an inherited condition? There is no known inheritance pattern for macular holes, and there is no evidence that macular holes are carried from one generation to another. If I have a macular hole in one eye, does it happen in the other? Depending upon the degree of attachment or traction between the vitreous and the retina, there may be risk of developing a macular hole in the other eye. The ophthalmologist evaluating you can determine the status of the vitreous jell and its degree of traction on the retinal surface in the uninvolved eye, and can help to better define the risks to this eye. In those cases where the vitreous has already become separated from the retinal surface, there is very little chance of developing a macular hole. On the other hand, when the vitreous remains adherent and pulling on the macular region in both eyes, then there may be a more significant risk of developing a hole in the second eye. Is there anything that caused the macular hole, or is there anything that can be done to prevent a macular hole from developing in the other eye? In very rare instances, trauma or other conditions lead to the development of a macular hole. In the vast majority of cases, however, macular holes develop spontaneously. As a result, there is no known way to prevent their development through any nutritional or chemical means, nor is there any way to know who is at risk for developing a hole prior to its appearance in one or both eyes. Does it matter how long I have had the macular hole if I am interested in having surgery done? There is evidence in the scientific literature that macular holes present for less than six months have a better chance of repair and visual recovery than those present for more than six months. Studies have shown, however, that some vision improvement can take place in patients with more long-standing macular holes, but rapid evaluation and treatment is preferable in patients with this condition. If a macular hole exists in one eye, it is therefore very important to monitor for any vision changes in the second eye, and report these vision changes to your ophthalmologist immediately. If I have surgery, what type of vision improvement can be expected? Typically, for macular holes less than six months in duration, a vision improvement of approximately three lines on the eye chart (or 50% improvement) can be achieved. Obviously, this is an "average" visual improvement. Vision recovery varies on a patient-by-patient basis, and each patient must be evaluated on an individual basis and discuss with their physician the expectations for visual recovery. Some patients achieve only a small amount of vision recovery, while others achieve a more significant improvement. How important is it really to maintain the face-down position? Face-down positioning is crucial to the success of the operation. If a patient is not able to maintain face-down positioning, it is unlikely that the operation will succeed. Therefore, before macular hole surgery is considered, a patient should experiment at home with maintaining a face-down position for a period of time to ensure that they are able to comply with the restricted activities necessary in the postoperative period. Some patients, because of medical conditions or physical limitations, may be unable to comply with the positioning and would not likely be good candidates for this procedure. When will I get my vision back? During the postoperative period, the air bubble in the eye will be pressing on the macula to ensure closure of the hole. While the air bubble is present in the eye, the eye is unable to focus light properly, and therefore vision is significantly disrupted. Often patients are only able to see shapes, shadows or hand movements in front of their eyes while the bubble is large. As the bubble begins to shrink, usually between the third and fourth week, vision begins to return. Final vision recovery is often not achieved for 6-12 weeks following the operation after the bubble completely resolves, the macular hole heals, and a final prescription for glasses is given. For those patients who have not had cataract surgery, the vision may begin to exhibit gradual deterioration approximately 6-12 months after the operation as a cataract develops. Once cataract surgery is performed, vision would then typically return to its maximal level. Am I able to travel after macular hole surgery? Patients are not permitted to fly when there is a large air bubble present inside the eye. When a person travels by air, there are changes in air pressure which can result in expansion of the air bubble and increased eye pressure. In order to prevent this complication, patients are restricted from any type of air travel until the bubble is nearly gone, or small enough that the patient’s physician considers it safe to fly. Are there any special chemicals used to close the macular hole? When surgery is performed to close a macular hole, no laser treatment is applied to the hole itself, as laser can be damaging to the delicate central tissue of the macula. In order to avoid this damage, the air bubble alone is used to help provide the seal between the retina and the wall of the eye. Experiments have been performed in recent years in an attempt to determine if chemicals applied to the surface of the macular hole at the time of surgery will increase the success rate for the operation. Studies have not yet conclusively demonstrated that application of any chemicals are necessary to have a successful result from the surgical procedure. Macular Pucker Jason S. Slakter, MD The human eye is shaped like a ball, measuring approximately one inch across, and functions like a living camera. The front portion of the eye, consisting of the cornea (the clear cover of the eye), the lens and the iris (the colored portion of the eye), acts to focus light on the back of the eye, much like the lens and aperture system of a camera focuses light on a piece of film. The retina, similar to the photographic film itself, is a thin layer of tissue that lies against the back surface of the eye wall. The image obtained by the retina is transmitted via the optic nerve to the brain and forms the picture that we see. Unlike a camera, the image obtained by the retina is not of uniform clarity or sharpness. Only the central portion of the retina, the macula, is sensitive enough to provide high quality vision for tasks such as reading, watching television, or driving. The macula is a very small area, with the central portion being only about the size of the head of a pin. It is only this specialized area of the retina, the macula, that is capable of the detailed vision necessary for many daily tasks. In order to maintain its round structure, the central portion of the eye is filled with a jelly-like substance known as the vitreous. At birth and through early years, the vitreous has a fairly solid structure, having a consistency somewhat between Jell-O and molasses. As a person ages, however, the vitreous jell begins to shrink and becomes more condensed toward the front part of the eye, being replaced by liquid as the process continues. As the vitreous shrinks, it pulls away from the surface of the retina. In most cases, this pulling away or vitreous separation occurs without any negative effect. A patient may notice floaters but no significant visual damage occurs. In some individuals, however, there may be an area where the vitreous is firmly attached to the surface of the retina. As the shrinkage and forward movement of the vitreous progresses, traction or pulling can be exerted on the retina, resulting in microscopic damage to its inner surface. When this focal area of damage or irritation occurs in the macular region, the retina initiates a healing response with mobilization and migration of cells found within the retina itself, which then spread outward along the surface of the retina, in an attempt to "heal" the area of damage. Unlike a macular hole, a full thickness defect or break in the retina has not taken place. Instead, only superficial irritation has occurred with a normal healing response taking place. This thin layer of scar tissue is known as a macular pucker. Macular pucker is known by a variety of names, including epiretinal membrane, surface wrinkling retinopathy, cellophane retinopathy, and internal limiting membrane disease. All of these names relate to the fact that there is a layer of thin scar tissue on the surface of the macula which resulting in mechanical wrinkling and distortion of the retina. Clinical photo of a macular pucker In most cases, the healing response is mild, and results in a very thin layer of cells lying on the surface of the retina. These cells may be clear and may produce no significant visual disturbance. In other cases, this healing process may progress, with an overabundance of cells being produced, forming a thicker, more opaque membrane or layer of scar tissue on the surface of the macula. In most patients, even with the formation of a significant macular pucker or epiretinal membrane, there is very slow growth that takes place, and eventually the scar tissue stops proliferating or extending. With time, contraction or pulling of the cells may take place, causing a wrinkled or rippled appearance to this scar tissue. Since the scar cells are attached to the retina, the retina itself becomes wrinkled in association with the progression of the scar. When this occurs in the central, critical portion of vision, the macula, visual symptoms may result. The symptoms of a macular pucker are common to many conditions affecting the central part of the retina. These include: distortion in lines or letters while reading, a decrease in central vision for distance and reading activities, and blurring or distortion of images when looking at television or in the theater. The diagnosis of a macular pucker is made when an ophthalmologist performs a dilated retinal examination and examines the back of the eye. A fluorescein angiogram (injection of a dye into the vein, with photographs taken of the back of the eye) may be recommended to evaluate the situation and determine if leakage or swelling of the retina is taking place as a result of the scar tissue being present on the surface of the macula. In most cases, no treatment is recommended for macular pucker. This is due to the fact that the visual distortion and decreased reading and distance vision is minimal in the majority of patients. Although some mild visual problems are noted, these are usually easily adjusted to and pose no limitation on full activity. In some instances, however, the distortion and vision loss may be significant. There may be an inability to perform certain daily tasks such as reading or driving. It is at this point, that consideration for surgical repair would be entertained. Surgery would also be considered if vision loss is moderate, but there is evidence on the fluorescein angiogram of significant leakage posing a threat to permanent damage to central vision in those individuals. Repair of a macular pucker or epiretinal membrane is accomplished through use of vitreoretinal surgery. Using microsurgical instruments, a procedure known as a vitrectomy, the microscopic removal of vitreous jell from the center of the eye, is performed. Particular attention is paid from moving any vitreous attachment from the central macular region. Specialized microsurgical instruments are then used to gently peal and remove the scar tissue from the surface of the retina, relieving the traction and reducing the distortion to the retinal surface. During the course of the surgical procedure, a fluid which is chemically similar to the fluid naturally produced by cells inside of the eye is used to replace the vitreous. As part of the procedure, careful inspection for retinal tear or detachment formation is performed, which can occur in association with the development of a macular pucker or occur as a rare complication of the surgical procedure itself. If a tear or break is found, laser treatment may be applied to these areas. Unlike macular hole surgery, macular pucker surgery does not typically involve the use of an intraocular air bubble. As a result, no specialized positioning in the postoperative period is required. However, in rare instances where retinal tears or detachments occur at the time of surgery, air bubbles and special positioning may be required. The surgical procedure itself is typically performed under local anesthesia and a patient may remain in the hospital overnight or may be scheduled for ambulatory surgery, able to return home by the end of the day of the surgical procedure itself. A postoperative examination within 24 hours of surgery is required in all cases. Regular follow-up examinations are performed during the first six weeks of recovery, and then at regular intervals after that. Patients typically utilize several eye drops applied to the operated eye over the course of several weeks following the surgical procedure. Approximately 10-12 weeks after surgery, when the eye has recovered from the surgery and the macula has had a chance to return to a more normal configuration, the patient is measured for glasses. Full visual recovery may not occur for at least 3-4 months following the procedure. As with all surgical procedures, there are potential complications and side-effects associated with repair of macular pucker. As mentioned, these include a small percentage of patients that develop retinal tears or detachments during the procedure or in the immediate postoperative period. These problems are usually easily repairable. In patients who have not already undergone cataract surgery, development of a cataract may occur more rapidly following vitrectomy surgery. Surgical removal of the cataract and placement of an intraocular lens is then required. Frequently asked questions Are macular pucker, macular hole and macular degeneration related in any way? Macular pucker and macular hole both result from excessive traction and pulling by the vitreous on the surface of the retina. If mild to moderate traction occurs as the vitreous separates from the retinal surface, then a healing response may take place resulting in a macular pucker. However, if the traction is more severe, a true defect in the retina may occur resulting in the formation of a macular hole. Macular degeneration, on the other hand, is a distinct entity involving the tissues underlying the retina. There is no direct relationship between macular degeneration and these other two conditions. Is there anything that caused the macular pucker specifically or anything that can be done to prevent it from getting worse or occurring in the other eye? Macular pucker results from the separation of the vitreous from the surface of the retina. In most cases, this is a spontaneous event with no particular cause or means for prevention. In some instances, trauma or a severe blow to the head or eye might cause a more rapid separation of the vitreous and a more aggressive healing response to occur, thus resulting a more visually significant macular pucker. In some cases, macular puckers result from pulling on the peripheral retina and formation of a retinal break or tear. The tear or break in the retina should be treated, and- then the macular pucker itself observed or repaired depending upon the degree of vision loss that it is causing. There are no means to prevent a pucker from developing spontaneously, nor is there any known treatment to either medically or nutritionally slow down the progression of the macular pucker or to reverse its visual effects. If I have surgery, what type of vision improvement can be expected? Typically, a vision improvement of about 3 lines in an eye chart (or 50% improvement in vision) can be achieved. This is an "average" vision improvement, however. Recovery does vary on a patient-by-patient basis. Each individual must be evaluated and discuss with their physician the expectations for visual recovery. Some patients do achieve only a small amount of vision recovery, while others achieve a more significant degree of improvement. One of the major effects of surgery is a reduction in the degree of distortion that is often a major complaint of patients with macular pucker. How soon will I get my vision back? Vision improvement following macular pucker surgery typically occurs gradually as the eye heals. Usually there is some vision improvement noted in the first 6 weeks, but a final visual recovery is not achieved in many patients until a full 3 months has elapsed from the time of surgery. Once the macula has had a chance to heal and restore more normal function, a final prescription for glasses is given. For patients who have not had cataract surgery, vision may begin to exhibit gradual deterioration over 1-2 years following the vitrectomy for removal of the macular pucker, as a cataract develops. Once cataract surgery is performed, vision would then typically return to its maximal level. Are there any restrictions on travel after macular pucker surgery? Only patients who have intraocular air bubbles have specific restrictions on flying. Obviously, regular follow-up examinations are required in the first few weeks after surgery, and a patient must be available and close to the physician's office in order to be able to keep these follow-up appointments. Does the scar tissue or the macular pucker ever grow back? In a small number of cases, the macular pucker may recur or grow back as a result of reactivation of the healing process. The reason that macular puckers grow back in some patients and not in others is poorly understood. It appears that the body recognizes the surgical procedure itself as a form of injury or irritation to the retina, and restarts the healing process that caused the macular pucker in the first place. Fortunately, instances of regrowth of macular pucker are very uncommon, and stability of vision is more typically achieved after surgery Proliferative Diabetic Retinopathy By K. Bailey Freund, MD Proliferative diabetic retinopathy is a major cause of visual loss in diabetic patients. Patients at risk for this complication require frequent eye exams and often immediate treatment once the disorder is recognized. As retinal blood vessels become damaged and close off in diabetic retinopathy, the peripheral portions of the retina lose their source of nutrition and and stop functioning properly. This process is know as retinal ischemia and is believed to be the first step in the development of proliferative diabetic retinopathy (PRD). Presumably, the ischemic (nutrient-starved) retina sends out a chemical message which leads to the growth of new blood vessels (neovascularization) in the eye. These vessels often grow on the surface of the retina, at the optic nerve, or in the front of the eye on the iris. Color retinal photograph centered on the optic nerve (left eye). This picture demonstrates proliferative diabetic retinopathy. Abnormal vessels (neovascularization) are growing from the nerve over the retinal surface and into the vitreous jelly (the clear substance which fills the eye). Drawing of proliferative diabetic retinopathy. Unfortunately, neovascularization is never good for the eye. The new vessels cannot replace the flow of necessary nutrients and, instead, can cause many problems such as vitreous hemorrhage (bleeding into the gel which fills the eye), retinal detachment, and uncontrolled glaucoma (high pressure in the eye). These problems occur because new vessels are fragile and are prone to bleed. As they grow within the eye they, may exert traction on adjacent structures. This pulling may produce a distortion of the retina and even lead to a retinal detachment. When the vessels grow in the front of the eye on the colored iris (iris neovascularization) they can clog the fluid outflow channels and cause the pressure in the eye to become very high. This is called neovascular or rubeotic glaucoma. Color retinal photograph centered on the optic nerve (left eye). This picture demonstrates proliferative diabetic retinopathy. Abnormal vessels (neovascularization) are growing from the nerve over the retinal surface and into the vitreous gel. Some of these vessels have bled into the vitreous (vitreous hemorrhage). Color retinal photograph demonstrating severe proliferative diabetic retinopathy. Abnormal vessels (neovascularization) are growing from the nerve over the retinal surface producing a tractional retinal detachment. In advanced cases of proliferative diabetic retinopathy such as this, a surgical treatment known as a vitrectomy may be required to flatten the retina. If caught in its early stages, proliferative diabetic retinopathy can sometimes be arrested with panretinal photocoagulation. In some cases, vitrectomy surgery is necessary. Retinal Detachment By John A. Sorenson, MD INTRODUCTION The retina is the neurosensory tissue that lines the back wall of the eye. Like the film in a camera, the retina is responsible for creating the images that one sees. The center of the retina is called the macula and is the only part capable of fine detailed vision, i.e. reading vision, recognizing faces, etc. The remainder of the retina , the peripheral retina, is for side vision. The retina outside the center of the macula, which makes up more than 95% of the retina, is not capable of the fine detailed vision. When the retina detaches, it separates from the back wall of the eye and is removed from its blood supply and source of nutrition. The retina will degenerate and lose its ability to function if it remains detached. Central vision will be lost if the macula remains detached. The causes of retinal detachment can be divided into three main categories: 1. Rhegmatogenous retinal detachment: due to a retinal break or tear that allows the liquid vitreous that fills the center of the eye ball to pass through the break and detach the retina. This is the most common type of detachment. 2. Exudative retinal detachment: due to leakage from under the retina which creates fluid (exudate) that detaches the retina. Tumors and inflammatory disorders can create exudative detachments. 3. Traction retinal detachments: due to pulling on the retina usually from fibro-vascular tissue within the vitreous cavity. Proliferative diabetic retinopathy is a common cause of traction retinal detachments. RHEGMATOGENOUS RETINAL DETACHMENTS This is the most common type of retinal detachment and usually occurs when the vitreous separates from the back wall of the eye. The vitreous is the clear gel that fills the central cavity of the eye. The formed vitreous gel liquefies with age and eventually falls away or separates from the retina. This is called a posterior vitreous detachment (PVD) and is a normal event occurring in most people sometime between 40-70 years of age. As the gel separates and falls away from the center of the retina, one will often see floaters. These appear as dots, spots, or curly lines that appear suspended in front of you and move with your eye. People often think these floaters are flying bugs. Flashes of light are also a common symptom of a PVD. These are due to pulling on the retina as the gel separates. This pulling stimulates the retina, resulting in a flash of light. If a retinal blood vessel is broken from the pulling, a vitreous hemorrhage can occur. A small amount of blood may be seen by the patient as a shower of spots. Larger hemorrhages can cause large dark blobs in the visual field or a overall decrease in vision. If the gel is abnormally adherent to the retina or the retina is weak in a certain area, a retinal tear can occur as the gel separates and pulls away from the retina. Fortunately, the great majority of PVDs do not cause a retinal tear. Sometimes, a PVD can occur without any symptoms, and sometimes, there can be lots of annoying symptoms without any retinal breaks. Clinical picture and drawing of two retinal tears with detachment (blue area). A retinal detachment can occur once there is a retinal break. The liquid vitreous passes through the break and goes under the retina. The retina will then start to detach from the underlying tissue. Since most tears occur in the peripheral retina, the detachment will first cause loss of a portion of the side vision. This can be seen as a curtain or dark shadow involving the peripheral vision. As the detachment extends towards the macula, the shadow will also enlarge. Central vision will be lost if the macula detaches. Without surgical repair, most rhegmatogenous detachments will eventually involve the entire retina and all vision will be lost. Cross-section of eye with retinal detachment If a retinal break is discovered before a detachment occurs, it can be treated to prevent the retina from detaching. Usually the laser is used to treat a retinal break. The laser creates a series of burns surrounding the break which eventually scar and seal the retina to the underlying tissue. This prevents fluid (liquid vitreous) from passing through the break and detaching the retina. Rarely, the laser cannot be used and a retinal cryoprobe is used to treat the break. The cryoprobe creates a freezing reaction which will produce scarring to surround the break. Once a detachment occurs it is almost always too late to use the laser or cryoprobe. This is why it is so important to be examined immediately if you have symptoms of a PVD (flashes, floaters, shower of spots). A thorough dilated examination with indirect ophthalmoscopy, contact lens exam and scleral depression is required to find retinal breaks and other areas at risk for detaching. If no breaks are found at the initial exam, it is important to be re-examined within 1-2 weeks or sooner if new symptoms develop. The vitreous can continue to separate and pull on the retina for several weeks or longer and the retina can develop a tear during this time. Even if a tear is discovered and treated, follow-up examination is necessary to be sure the laser reaction is working and that no additional tears have developed. Not all retinal breaks need to be treated . Many people have round or atrophic holes in their retina that are discovered on routine examination and, usually, these do not need to be treated. In general , however, if a retinal break is discovered in association with new symptoms of a PVD or there are other high risk factors for a retinal detachment (family history, very near sighted, detachment in other eye, history eye trauma, prior cataract surgery, etc...) treatment is indicated. Treatment of retinal breaks with the laser or cryoprobe is very successful and retinal detachment can usually be avoided if the retinal breaks are identified and treated. Unfortunately, sometimes a retinal tear will lead almost immediately to detachment or there may not be any symptoms of a PVD, retinal tear or detachment. For these and other reasons, many people will have a retinal detachment when first examined and will almost always require some sort of surgical repair. REPAIR OF RHEGMATOGENOUS RETINAL DETACHMENT Fortunately, over 90% of retinal detachments can be repaired with a single procedure. Currently, there are 3 different surgical approaches to repairing a detachment: scleral buckle procedure, vitrectomy and pneumatic retinopexy. 1. Scleral buckle: This surgical procedure has been in use for more than 30 years, and, until approximately 20 years ago, was the only procedure available. It is still commonly used for rhegmatogenous retinal detachments, especially when there are no complicating factors. The procedure involves localizing the position of all the retinal breaks, treating all retinal breaks with the cryoprobe and supporting all the retinal breaks with a scleral buckle. The buckle is usually a piece of silicone sponge or solid silicone. The type and shape of the buckle varies depending on the location and number of retinal breaks. The buckle is sewn onto the outer wall of the eyeball (sclera) to create an indentation or buckle effect inside the eye. The buckle is positioned so that it pushes in on the retinal break and effectively closes the break. Once the break is closed, the fluid under the retina (subretinal fluid) will usually spontaneously resolve over 1-2 days. Sometimes the surgeon elects to drain the subretinal fluid at the time of surgery. Most often, a scleral buckle procedure can be done with local anesthesia and as same day surgery ( in and out of the hospital on the same day). Postoperatively, there are usually no positioning requirements and one can resume most activities within several days (except for anything that would jar the head). 2. Vitrectomy: Usually referred to as a trans pars plana vitrectomy (TPPV), this procedure was first used ~ 20 years ago and has been continuously refined and improved since then. It is most commonly used for traction retinal detachments but is also used for rhegmatogenous detachments especially if they are associated with vitreous traction or vitreous hemorrhage. The procedure involves making small incisions into the wall of the eye to allow the introduction of instruments into the vitreous cavity (the middle of the eyeball). The first part of the procedure usually is the removal of the vitreous using a vitreous cutter. Then, depending on the type and cause of the detachment, a variety of instruments (scissors, forceps, pics, lasers, etc...) and techniques (excision of tractional bands, air-fluid exchange, silicone oil fill, etc...) are used to reattach the retina. A TPPV can also usually be done as same day surgery and with local anesthesia. It is sometimes important to maintain a specific head position after surgery to keep the retina attached. More information regarding vitrectomy surgery can be found on the vitrectomy page. 3. Pneumatic retinopexy: Over the past 10 years, this has become a popular way to repair a straight-forward rhegmatogenous retinal detachment, especially if there is a single break located in the superior portion of the retina. This procedure involves injecting a gas bubble into the middle part of the eye (vitreous cavity). It is then critical to position oneself so that the gas bubble covers the retinal break. If the break can be covered by the bubble, the subretinal fluid will usually resolve within 1-2 days. The retinal tear is either treated with cryopexy before the bubble is injected or with laser after the retina has flattened. The main advantages of this approach are that it can be done in the office, thus avoiding hospitalization and that it avoids some of the complications of scleral buckling surgery, although it has its own set of complications. The main disadvantages are the requirement for precise head positioning for up to 7-10 days following the procedure and a slightly lower initial success rate as compared to a scleral buckle. If the retina is not reattached by a pneumatic retinopexy procedure, a scleral buckle and/or TPPV can be done at that point. SURGICAL RESULTS Approximately 90% of rhegmatogenous detachments can be initially repaired with one or a combination of these procedures. Sometimes, a scleral buckle is combined with a TPPV. If the retina does not reattach or detaches again after initial reattachment, it is usually due to the development of scar tissue on the surface of the retina and tractional forces within the vitreous cavity. If this happens following a scleral buckle procedure, it is often necessary to do a TPPV to repair the detachment. Sometimes, an intraocular gas bubble can be injected and the retina reattached following positioning. If a TPPV was done initially, it is often necessary to go back and do another TPPV to remove the new scar tissue and/or perform a scleral buckle. If a pneumatic retinopexy was the initial procedure, another pneumatic can be done or a scleral buckle or TPPV can be performed. As one can tell, there is no set way to repair a detachment and all the available procedures can be used in different combinations and sequences depending on the specific situation. VISUAL RESULTS The visual prognosis depends mainly on the pre-existing status of the retina before it detached. If the macula has not detached, the pre-existing vision will usually be retained following successful repair. However if the macula is detached and central vision is impaired by the detachment, there may be permanent loss of central vision even if the retina is successfully repaired. The longer the macula is detached, the more likely there will be loss of vision due to irreversible damage to the photoreceptor cells. In general, if the center of the macula is detached for more than 4-5 days, there will be significant loss of central vision following surgical reattachment. TRACTION RETINAL DETACHMENTS If a retinal detachment is primarily due to traction, it is termed a traction retinal detachment. The traction is usually due to proliferative fibro-vascular tissue within the vitreous cavity that pulls the retina away from the back wall of the eye. Proliferative diabetic retinopathy is a common cause of traction retinal detachments. In proliferative diabetic retinopathy, abnormal vessels (neovascularization) grow from the retinal surface onto the back surface of the vitreous. This fibrovascular tissue can then pull the retina away from the back wall of the eye, thus creating a traction retinal detachment. Another common cause is proliferative vitreoretinopathy (PVR). PVR is the most common cause of failure of a scleral buckle procedure for a rhegmatogenous retinal detachment and occurs ~ 10% of the time. It is due to proliferation of cellular membranes (essentially scar tissue) in the vitreous cavity and on the surface of the retina. These membranes can contract and detach the retina. A traction retinal detachment will usually need to be surgically repaired if it involves the macula. A TPPV is almost always required (see discussion of TPPV under Repair of Rhegmatogenous Retinal Detachments). Sometimes a scleral buckle is performed in conjunction with the TPPV, especially if there is a combined rhegmatogenous - traction detachment. A combined detachment usually occurs when the fibrovascular proliferation causing a traction detacment also pulls or rips a tear in the retina. Some traction detachments that involve the peripheral retinal and are not threatening the macula can be observed without surgery. The success rate and visual outcome of surgery for traction detachments depends mainly on the underlying cause of the detachment and the extent and location of involvement. Some traction detachments can be relatively easy to repair and others can be impossible to fix even with all the advanced surgical techniques that are available today. EXUDATIVE RETINAL DETACHMENTS Exudative detachments are due to leakage of fluid from the tissue layers under the retina rather than leakage of fluid vitreous from the middle of the eye through a retinal break. The most important factor in dealing with an exudative detachment is determining its cause. Many conditions can cause an exudative detachment including tumors, inflammatory disorders , connective tissue diseases and macular degenerative conditions. The evaluation of an exudative detachment will usually consist of a complete ophthalmologic examination including angiography and ultrasonography, and a complete medical work-up. The treatment will of course depend on the particular cause of the detachment. The visual prognosis also depends on the underlying etiology.
Common Office & Surgical Procedures- Handouts/PDF's
Vitrectomy ( Trans Pars Plana Vitrectomy ) By K. Bailey Freund, MD Vitrectomy is a microsurgical procedure in which specialized instruments and techniques are used to repair retinal disorders, many of which were previously considered inoperable. The initial step in this procedure is usually the removal of the vitreous gel through very small (~1.4mm) incisions in the eye wall, hence the name "vitrectomy". The vitreous is removed with a miniature handheld cutting device and replaced with a special saline solution similar to the liquid being removed from the eye. A high intensity fiberoptic light source is used to illuminate the inside of the eye while the surgeon works. The surgeon uses a specialized operating microscope and contact lenses, which allow a clear view of the vitreous cavity and retina at various magnifications. The procedure is performed in an operating room under local or (occasionally) general anesthesia. It can often be done as an ambulatory procedure. Although vitrectomy procedures are sometimes performed through incisions made near the front of the eye, most vitreoretinal surgeons enter the globe through a part of the eye known as the pars plana. This is why the procedure is often referred to as a trans pars plana vitrectomy (TPPV). Entering the eye through this location avoids damage to the retina and the crystalline lens (see figure below & anatomy section of this website). Instruments entering the eye through the pars plana (brown area). Vitreous gel is being removed . Trans pars plana vitrectomy (TPPV) is used to treat many different retinal disorders including those listed below (more information on some of these topics can be found elsewhere in our patient information section): 1. Proliferative diabetic retinopathy (including vitreous hemorrhage) 2. Macular hole 3. Epiretinal membrane (macular pucker) 4. Complicated, tractional or recurrent or retinal detachment 5. Intraocular infections (endophthalmitis) 6. Intraocular foreign body 7. Retained lens material or dislocated lens implants following cataract surgery 8. Giant retinal tears 9. Traumatic eye injuries Surgeon's view during vitrectomy surgery During vitrectomy surgery, the retinal surgeon may use a variety of special techniques to achieve the desired results, including: 1. Intraocular gases (usually either perfluropropane (C3F8) or sulfur hexafluoride (SF6)) when mixed with sterile air have the property of remaining in the eye for extended periods of time (up to two months). They are eventually replaced by the eyes own natural fluid. Gas is useful for flattening a detached retina and keeping it attached while healing occurs. Gas injection is also used to close macular holes. It is frequently necessary to maintain a certain head position following surgery when gas is used (see Macular Hole page). Vision in a gas filled eye is usually rather poor until at least 50% of the gas is absorbed. Possible complications of intraocular gas include progression of cataracts and elevated eye pressure (glaucoma). It is unsafe to fly in a plane while gas remains in the eye. 2. Silicone oil is sometimes used instead of gas to keep the retina attached postoperatively. Silicone remains in the eye until it is removed (often necessitating a second surgery at a later date). This technique is advantageous when long term support ("tamponade") of the retina is required, for instance in the repair of very complicated retinal detachments. Unlike gas, patients are still able to see through clear silicone oil. Positioning is less critical with silicone oil, therefore, it may be used in patients unable to position postoperatively (i.e. children). Like gas, silicone oil can promote cataracts, cause glaucoma, and may damage the cornea. 3. Endophotocoagulation is the use of laser to treat intraocular structures. This modality is often used to treat retina tears in the setting of retinal detachment. Endophotocoagulation is frequently used to treat proliferative diabetic retinopthy as well. 4. Microsurgical instruments such as forceps, scissors and picks may be used to manipulate intraocular structures such as in the removal of scar tissue and foreign bodies. Literally hundreds of vitrectomy instruments are available to assist in different surgical maneuvers. Most of these vitreoretinal tools have a diameter of less than 1mm, making them some of the most precise and finely crafted instruments in the world today. 5. Endoscopy allows the surgeon to view the inside of the eye on a television monitor while treating intraocular structures. It is a helpful technique when the cornea or lens are cloudy and do not allow a clear view through the operating microscope. 6. Scleral buckling is sometimes combined with a vitrectomy procedure to add additional support to the re-attached retina (see Retinal Detachment page). 7. Lensectomy is the removal of the eye's crystalline lens during a vitrectomy procedure. This is sometimes performed when there is a cataract (clouding of the lens) which prevents the surgeon from adequately visualizing the internal structures. A lensectomy may also be necessary to gain access to and remove scar tissue during complicated retinal detachment or diabetic retinopathy procedures. The natural lens can be replaced with a clear lens implant at a later date or during the same surgical procedure. Lensectomy is usually performed using high frequency ultrasound (phacoemulsification) similar to routine cataract surgery. Vitrectomy surgery is a major medical advance which allows us to treat retinal diseases and prevent vision loss for patients who, in previous years, may have gone blind without this technique. A vitrectomy procedure usually takes about 1-2 hours but may take longer in complex cases or when combined with a scleral buckle or lensectomy. Risks of surgery include infection, bleeding, cataract, glaucoma, and detachment or re-detachment of the retina. Any of these complications can result in severe visual loss or even loss of the eye itself. It is important that you discuss the potential risks and benefits of this procedure with your surgeon before making a decision regarding treatment. |
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