by Samantha Power
August 31st, 2010
Limited Retinal Translocation-Limited retinal translocation is another treatment aimed at wet macular degeneration. In this procedure the retina is actually moved somewhat to allow laser treatments to be applied more successfully to abnormal blood vessel growth. The procedure is still in the macular degeneration treatments developmental stages in terms of approval for commercial applications. Surgical options for dry macular degeneration are proposed periodically. The methodologies change from procedure to procedure, but the general idea is the same.
Wednesday, September 1, 2010
Monday, August 23, 2010
Macular Degeneration Surgery
By Joven Villanueva
While the quest in searching for the cure of macular degeneration is on going. Many national eye centers are investigating new ways to treat the said illness. There are different options in managing macular degeneration as the illness has two types. The wet form which usually results to loss of vision due to no reliable treatment yet to be developed and the dry form accounting 90% of cases can still be managed and controlled if diagnosed at an early stage and by eating the right food rich in vitamins A, C, E and other supplements such as zeaxanthine and zinc - proven to be effective in slowing down the disease
Here are some optional treatments available for patients having the wet form of macular degeneration. First is Photodynamic therapy which uses a combination of both cold laser and light-sensitive drug destroying abnormal blood vessels as the drug travels to the unwanted vessels after it was injected from the arm. Another option is Laser therapy where high energy lights are used to destroy abnormal growing blood vessels.
The Cole eye institute is conducting experimental treatments such as a surgery to remove abnormal blood vessels and blood. A genetically engineered enzyme is used by the surgeon to dissolve blood clots under the macula. Another procedure is called Macular translocation.This is performed using a laser therapy to treat abnormal blood vessel. To prevent the formation of scar tissue and damage to retina, the surgeon rotates the retina in a healthy area.
The healing process may take three to six weeks. The doctor may request for an angiogram after the macular surgery to make sure that there are no additional blood leakage in the area. An additional laser treatment maybe performed if a problem was observed.
Macular degeneration is a medical condition resulting to loss of vision making it difficult to read and recognize faces. To better understand the patient's condition, print out some letters six inches high and try to identify them while looking it at straight ahead. Hold the paper slightly to the side. This visual impairment does not lead to total blindness and in most cases some vision remains.
This disease mostly affects older and adults 50 years old and above. In a recent study for macular degeneration it was found out that those patients aging sixty six to seventy four suffer from this illness. Mostly women are prone to macular degeneration compare to men and smokers of any gender are also part of the growing list as tobacco increase the risk in three folds due to the toxic effects in retina. It is even 50% risky for those who have relatives with muscular degeneration to develop the illness compare to those who doesn't have with only 12% probability. Caucasians are more prone to develop macular degeneration compare to other races.
Other than age and family history, there are factors that cause macular degeneration. These includes hypertension or commonly known as high blood pressure, obesity, and high fat intake.
Ophthalmologists diagnose macular degeneration by looking at the abnormal vessels under the retina. A dye is injected in the arm of the patient where pictures are taken by a special camera until it reaches the eye. Any changes in the retina as shown from the photographs taken will serve as a guide for treatment.
While the quest in searching for the cure of macular degeneration is on going. Many national eye centers are investigating new ways to treat the said illness. There are different options in managing macular degeneration as the illness has two types. The wet form which usually results to loss of vision due to no reliable treatment yet to be developed and the dry form accounting 90% of cases can still be managed and controlled if diagnosed at an early stage and by eating the right food rich in vitamins A, C, E and other supplements such as zeaxanthine and zinc - proven to be effective in slowing down the disease
Here are some optional treatments available for patients having the wet form of macular degeneration. First is Photodynamic therapy which uses a combination of both cold laser and light-sensitive drug destroying abnormal blood vessels as the drug travels to the unwanted vessels after it was injected from the arm. Another option is Laser therapy where high energy lights are used to destroy abnormal growing blood vessels.
The Cole eye institute is conducting experimental treatments such as a surgery to remove abnormal blood vessels and blood. A genetically engineered enzyme is used by the surgeon to dissolve blood clots under the macula. Another procedure is called Macular translocation.This is performed using a laser therapy to treat abnormal blood vessel. To prevent the formation of scar tissue and damage to retina, the surgeon rotates the retina in a healthy area.
The healing process may take three to six weeks. The doctor may request for an angiogram after the macular surgery to make sure that there are no additional blood leakage in the area. An additional laser treatment maybe performed if a problem was observed.
Macular degeneration is a medical condition resulting to loss of vision making it difficult to read and recognize faces. To better understand the patient's condition, print out some letters six inches high and try to identify them while looking it at straight ahead. Hold the paper slightly to the side. This visual impairment does not lead to total blindness and in most cases some vision remains.
This disease mostly affects older and adults 50 years old and above. In a recent study for macular degeneration it was found out that those patients aging sixty six to seventy four suffer from this illness. Mostly women are prone to macular degeneration compare to men and smokers of any gender are also part of the growing list as tobacco increase the risk in three folds due to the toxic effects in retina. It is even 50% risky for those who have relatives with muscular degeneration to develop the illness compare to those who doesn't have with only 12% probability. Caucasians are more prone to develop macular degeneration compare to other races.
Other than age and family history, there are factors that cause macular degeneration. These includes hypertension or commonly known as high blood pressure, obesity, and high fat intake.
Ophthalmologists diagnose macular degeneration by looking at the abnormal vessels under the retina. A dye is injected in the arm of the patient where pictures are taken by a special camera until it reaches the eye. Any changes in the retina as shown from the photographs taken will serve as a guide for treatment.
Wednesday, August 18, 2010
Epidemiolgy and Burden of Retina Disease
By Nancy M. Holekamp, MD
Age-related macular degeneration. The Eye Disease Prevalence Group has estimated that 1.75 million people in the United States have advanced age-related macular degeneration (AMD), including neovascular AMD or geographic atrophy, but not necessarily involving the foveal center, with the highest prevalence in adults older than 80 years of age.1 These numbers are estimated to increase substantially in the coming decades.
The numbers are huge, but what impact does AMD have on our patients? AMD is associated with an increased incidence of depression, mortality, and a greater need for assistance for daily tasks. In a quality-oflife study that was part of the Submacular Surgery Trials (SSTs), patients were asked to rate their current vision during phone interviews. Patient scores were converted to a preference value scale ranging from 1 (perfect health with perfect vision) to 0 (death). A mean preference value of 0.64 for subfoveal choroidal neovascularization (CNV) suggests a profound impact on quality of life. The impact is reported as greatest in those with the most severe loss of vision, but even patients with visual acuity of at least 20/40 in one eye had relatively low preference values.2 This is striking because it is right between having chronic renal failure and symptomatic HIV/AIDS (Figure 1). Clearly, AMD has a significant impact on the quality of life of individuals.
Diabetic retinopathy. It is well known that we are in the midst of an epidemic of obesity and diabetes in the United States. The rates of both have increased dramatically from 1990 to 2001, particularly in the southeast (Figure 2) and the increase in people with diabetes directly correlates to the rise in obesity.3 An estimated 18.2 million people had diabetes in the United States in 20023 and diabetes has been estimated to affect 151 million people worldwide, and is projected to increase to 324 million by 2025.4 It is also estimated that 35% of any diabetic population will have diabetic retinopathy.5 We know this from the Beaver Dam Eye Study. In terms of costs, the direct and indirect costs for diabetes were estimated at $132 billion in 2002.6 Almost $1 out of every $5 in the United States spent on healthcare is for patients with diabetes. Diabetes has an enormous impact on patients’ quality of life and represents a large economic issue.
Retinal vein occlusion. Retinal vein occlusion (RVO) is the second most common retinal disease after diabetic retinopathy. The Beaver Dam Study reported a prevalence of 0.6% in patients older than 43 years and the same study reported a 15-year cumulative incidence of BRVO of 1.8%.7 Although these numbers may sound low, the average age of these patients is 65 and this age group may have a host of comorbidities (eg, hypertension, vascular disease, diabetes). RVOs share risk factors with myocardial infarction (MI),8 stroke, and other arterial thrombotic events.9 In a study that is currently in press,10 we reviewed the records of 4,500 patients with RVO and compared them with 13,500 patients who were age-matched controls. We found that patients with RVO had significantly higher likelihood of having angina, cardiac arrhythmia, congestive heart failure, diabetes, heart disease, MI or stroke, hyperlipidemia, and hypertension (P=.001) The incidence of RVOs continues to increase as the incidence of diabetes increases and the population ages.
EVIDENCE-BASED MEDICINE
Evidence-based medicine is the practice of medicine based on the best scientific data available. The questions are, “How much evidence do you need?” and “How much science is behind it?”
These are the various levels of evidence. The weakest is the single-case report, which is level 5 evidence. The second weakest is the case series without a comparison group (level 4). Level 3 evidence consists of nonrandomized clinical trials that may compare two groups that are not concurrent or randomized. A level 2 clinical trial is similar to a phase 2 US Food and Drug Administration (FDA) clinical trial—it is randomized and controlled but it has a high type-1 error, where a trend is apparent and may be significant, but the number of patients is insufficient. A type-2 error is when a treatment difference likely exists but, again, there are not enough patients to isolate the difference.
Level 1 evidence is from randomized, prospective, controlled trials, with a low type-1 and type-2 errors. These are the phase 3 clinical trials that eventually lead to drug approval by the FDA. The key to level 1 evidence is a well-designed study and a large number of patients.
CLINICAL TRIAL DESIGN: WHY IS IT IMPORTANT?
In medicine we prefer level 1 trials because of random assignment to treatment or control; the concurrent enrollment that ensures patients are being treated in a similar manner; the large numbers of patients; and the masking of the investigators. The standardized follow up is also important to the significance of outcomes. By controlling these variables, we are able to clinically treat patients in the most scientific manner. My colleague Kuldev Singh, MD, who is a glaucoma specialist has said, “This term [randomized, controlled] allows the investigator to disarm the novice scientific critic, while impugning lesser prospective and all retrospective studies, not to mention case series and reports.” The randomized, controlled study is at the top of the food chain.
A case example of using low-level evidence-based medicine upon which to base treatment decisions is that of bevacizumab (Avastin, Genentech) for treating AMD. In August 2005, there was one case report (level 5 evidence) demonstrating improvement on optical coherence tomography (OCT) for a patient nonresponsive to pegaptanib sodium (Macugen, Eyetech/Pfizer) for AMD in the published literature.11 Simultaneously, Philip Rosenfeld, MD, PhD, one of the authors of the aforementioned case report, presented a paper (level 4 evidence) at the American Society of Retina Specialists in Montreal on a series of patients with exudative AMD who benefited from intravitreal bevacizumab. Clearly, the “bevacizumab for AMD” era was ushered in using the least convincing type of evidence.
Unlike bevacizumab, ranibizumab (Lucentis, Genentech) was subject to two phase 3 randomized, controlled clinical trials sponsored by industry (MARINA ANCHOR) that resulted in FDA approval. The extent to which the efficacy and safety of ranibizumab has been scrutinized is to the highest level.
But can you have a randomized, controlled trial for every disease and treatment? Paul Lichter, MD, said, “Authors of case reports, retrospective studies, and other manuscripts covering the gamut of imperfect clinical projects often conclude their papers by calling for a randomized, controlled, collaborative clinical trial. While I have no idea how many times such statements are made, there is no question that these pronouncements are abundantly more frequent then the clinical trials that result from them.”
CRITERIA FOR CONDUCTING A LEVEL 1 CLINICAL TRIAL
Clearly, a level 1 clinical trial cannot be conducted for every clinical situation. My four criteria for conducting a randomized, controlled clinical trial include the following:
* The disease must represent a significant health problem. An example of what can be called an questionable effort is in 1993 when the Canadian Ophthalmology Study Group conducted a multicenter randomized, controlled clinical trial to compare the argon green vs krypton red laser for choroidal neovascularization (CNV) in AMD.12 The comparison of these lasers was not a burning issue for the health care system.
* There must be scientific plausibility of benefit. In other words, there has to be some biologic basis for believing that a treatment works. An example from the AMD literature is subfoveal laser for CNV.13 There was no basis to suggest that applying laser to a patient’s fovea would be beneficial.
* A plausible, biologic benefit must exist. In other words, the early data on a new treatment should suggest the possibility of benefit. A good example of this is the Submacular Surgery Trials in AMD where early pilot data did not show any benefit to submacular surgery over laser photocoagulation.14 The eventual the long-term data supported this conclusion.
* Sufficient numbers of patients must be enrolled. If a study cannot recruit enough patients, it will not succeed. For example, it was almost impossible to recruit patients into the Macular Translocation clinical trial because they were randomized to either photodynamic therapy—a relatively painless 15-minute office-based laser procedure— or to macular translocation, which had a 25% complication rate at the time they were trying to enroll.15
The clinical trials’ registry, www.clinicaltrials.gov, currently lists 530 clinical trials for the treatment of AMD. Of those 200 trials are open and actively recruiting patients. Eighty-seven of these are randomized and controlled. Those of us in the field of ophthalmology and the subspecialty of retina are fortunate to be part of a profession that is committed to providing the best scientific evidence for its members. We have a long, proud history of practicing evidence-based medicine and performing randomized clinical trials in our field.
NON-INFERIOR CLINICAL TRIALS
There are basically three types of trial design: superiority, equivalence, and non-inferiority. The Comparisons of Age- Related Macular Degeneration Treatments Trials (CATT) is a non-inferiority trial comparing intravitreal ranibizumab to intravitreal bevacizumab. The margin of non-inferiority must be pre-specified in the design protocol to construct a two-sided, 95% confidence interval (CI) to determine the true difference between the agents. To be able to declare bevacizumab non-inferior, that interval must lay entirely on the positive side of the non-inferior margin.
Figure 3 helps illustrate how the results of a non-inferiority trial are interpreted. Applied to the CATT, if proved non-inferior, bevacizumab is either almost as good as, equivalent to, or better than ranibizumab. If bevacizumab fails non-inferiority then it is either equivalent, almost as good as, or inferior to ranibizumab. All of those possibilities exist.
The major criteria for non-inferiority clinical trials are:
1) historical evidence that the reference drug works (ie, MARINA and ANCHOR);
2) trial design must be the same as the reference trial (ie, the CATT has same design as MARINA and ANCHOR);
3) trial conduct must be the same (ie, many of the clinical sites from MARINA and ANCHOR are also sites for the CATT);
4) the non-inferior margin (minus delta) must be acceptable (ie, six letters for the CATT).
In addition to the CATT, there are two other non-inferiority trials in AMD: HARBOR (A Study of Ranibizumab Administered Monthly or on an As-Needed Basis in Patients With Subfoveal Neovascular Age-Related Macular Degeneration) and VIEW I (VEGF Trap-Eye: Investigation of Efficacy and Safety in Wet AMD). These are both similar to MARINA and ANCHOR in historical evidence, trial design and trial conduct, and have an acceptable non-inferior margin.
SUMMARY
The best way to practice evidence-based medicine is with phase 3, randomized, and controlled trials. The requirements for level 1 clinical trials do not necessarily constitute a “cookbook” for successful trials; rather, they provide guidelines for those who are designing and participating in clinical trials.
Finally, evidence alone is never sufficient information to make a clinical decision—there are many factors to be taken under consideration. When treating our patients, we consider several factors including a patient’s values, socio-economic status, and age; however we should rely on three main components: our years of clinical experience, the patient’s particular circumstances, and what we have learned from evidence-based medicine.
1. Friedman DS, O’Colmain BJ, Muñoz B, et al; The Eye Diseases Prevalence Research Group. Prevalence of age-related macular degeneration in the United States. Archives of Ophthalmology. 2004;122:564-572.
2. No authors listed. Submacular surgery trials randomized pilot trial of laser photocoagulation versus surgery for recurrent choroidal neovascularization secondary to age-related macular degeneration: II. Quality of life outcomes submacular surgery trials pilot study report number 2. Am J Ophthalmol. 2000;130(4):408-418.
3. National Institute of Diabetes and Digestive and Kidney Diseases. National Diabetes Statistics Fact Sheet: General Information and National Estimates on Diabetes in the United States. Bethesda, MD, US Department of Health and Human Services, National Institutes of Health, 2003.
4. King H, Rewers M. Global estimates for prevalence of diabetes mellitus and impaired glucose tolerance in adults: WHO Ad Hoc Diabetes Reporting Group. Diabetes Care. 1993;16:157–177.
5. Beaver Dam Eye Study.
6. Hogan P, Dall T, Nikolov P; American Diabetes Association. Economic costs of diabetes in the US in 2002. Diabetes Care. 2003;26(3):917-932.
7. Klein R, Klein BE, Moss SE, Linton KL. Beaver Dam Eye Study. Retinopathy in adults with newly discovered and previously diagnosed diabetes mellitus. Ophthalmology. 1992;99(1):58-62.
8. National Heart Lung and Blood Institute. Heart attack. Available at http://www.nhlbi.nih.gov/health/dci/Diseases/HeartAttack/HeartAttack_WhatIs.html.
9. Thom T, Haase N, Rosamond W, et al; American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics-2006 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Committee. Circulation. 2006;113:85-151.
10. Holekamp N. Arch Ophthalmol. In press.
11. Rosenfeld PJ, Moshfeghi AA, Puliafito CA. Optical coherence tomography findings after an intravitreal injection of bevacizumab (avastin) for neovascular age-related macular degeneration. Ophthalmic Surg Lasers Imaging. 2005;36(4):331-335.
12. The Canadian Ophthalmology Study Group. Argon green vs krypton red laser photocoagulation of extrafoveal choroidal neovascular lesions. One-year results in age-related macular degeneration. Arch Ophthalmol. 1993;111:181-185.
13. Macular Photocoagulation Study Group. Visual outcome after laser photo- coagulation for subfoveal neovascularization secondary to age-related macular degeneration. The influence of initial lesion size and initial visual acuity. Arch Ophthalmol. 1994;112:480–488.
14. Bressler NM, Bressler SB, Hawkins BS, Marsh MJ, Sternberg P Jr, Thomas MA; Submacular Surgery Trials Pilot Study Investigators. Submacular surgery trials randomized pilot trial of laser photocoagulation versus surgery for recurrent choroidal neovascularization secondary to age-related macular degeneration: I. Ophthalmic outcomes submacular surgery trials pilot study report number 1. Am J Ophthalmol. 2000;130(4):387-407.
15. Hawkins BS, Bressler NM, Miskala PH, et al; Submacular Surgery Trials (SST) Research Group. Surgery for subfoveal choroidal neovascularization in age-related macular degeneration: ophthalmic findings: SST report no. 11. Ophthalmology. 2004;111(11):1967-1980.
Age-related macular degeneration. The Eye Disease Prevalence Group has estimated that 1.75 million people in the United States have advanced age-related macular degeneration (AMD), including neovascular AMD or geographic atrophy, but not necessarily involving the foveal center, with the highest prevalence in adults older than 80 years of age.1 These numbers are estimated to increase substantially in the coming decades.
The numbers are huge, but what impact does AMD have on our patients? AMD is associated with an increased incidence of depression, mortality, and a greater need for assistance for daily tasks. In a quality-oflife study that was part of the Submacular Surgery Trials (SSTs), patients were asked to rate their current vision during phone interviews. Patient scores were converted to a preference value scale ranging from 1 (perfect health with perfect vision) to 0 (death). A mean preference value of 0.64 for subfoveal choroidal neovascularization (CNV) suggests a profound impact on quality of life. The impact is reported as greatest in those with the most severe loss of vision, but even patients with visual acuity of at least 20/40 in one eye had relatively low preference values.2 This is striking because it is right between having chronic renal failure and symptomatic HIV/AIDS (Figure 1). Clearly, AMD has a significant impact on the quality of life of individuals.
Diabetic retinopathy. It is well known that we are in the midst of an epidemic of obesity and diabetes in the United States. The rates of both have increased dramatically from 1990 to 2001, particularly in the southeast (Figure 2) and the increase in people with diabetes directly correlates to the rise in obesity.3 An estimated 18.2 million people had diabetes in the United States in 20023 and diabetes has been estimated to affect 151 million people worldwide, and is projected to increase to 324 million by 2025.4 It is also estimated that 35% of any diabetic population will have diabetic retinopathy.5 We know this from the Beaver Dam Eye Study. In terms of costs, the direct and indirect costs for diabetes were estimated at $132 billion in 2002.6 Almost $1 out of every $5 in the United States spent on healthcare is for patients with diabetes. Diabetes has an enormous impact on patients’ quality of life and represents a large economic issue.
Retinal vein occlusion. Retinal vein occlusion (RVO) is the second most common retinal disease after diabetic retinopathy. The Beaver Dam Study reported a prevalence of 0.6% in patients older than 43 years and the same study reported a 15-year cumulative incidence of BRVO of 1.8%.7 Although these numbers may sound low, the average age of these patients is 65 and this age group may have a host of comorbidities (eg, hypertension, vascular disease, diabetes). RVOs share risk factors with myocardial infarction (MI),8 stroke, and other arterial thrombotic events.9 In a study that is currently in press,10 we reviewed the records of 4,500 patients with RVO and compared them with 13,500 patients who were age-matched controls. We found that patients with RVO had significantly higher likelihood of having angina, cardiac arrhythmia, congestive heart failure, diabetes, heart disease, MI or stroke, hyperlipidemia, and hypertension (P=.001) The incidence of RVOs continues to increase as the incidence of diabetes increases and the population ages.
EVIDENCE-BASED MEDICINE
Evidence-based medicine is the practice of medicine based on the best scientific data available. The questions are, “How much evidence do you need?” and “How much science is behind it?”
These are the various levels of evidence. The weakest is the single-case report, which is level 5 evidence. The second weakest is the case series without a comparison group (level 4). Level 3 evidence consists of nonrandomized clinical trials that may compare two groups that are not concurrent or randomized. A level 2 clinical trial is similar to a phase 2 US Food and Drug Administration (FDA) clinical trial—it is randomized and controlled but it has a high type-1 error, where a trend is apparent and may be significant, but the number of patients is insufficient. A type-2 error is when a treatment difference likely exists but, again, there are not enough patients to isolate the difference.
Level 1 evidence is from randomized, prospective, controlled trials, with a low type-1 and type-2 errors. These are the phase 3 clinical trials that eventually lead to drug approval by the FDA. The key to level 1 evidence is a well-designed study and a large number of patients.
CLINICAL TRIAL DESIGN: WHY IS IT IMPORTANT?
In medicine we prefer level 1 trials because of random assignment to treatment or control; the concurrent enrollment that ensures patients are being treated in a similar manner; the large numbers of patients; and the masking of the investigators. The standardized follow up is also important to the significance of outcomes. By controlling these variables, we are able to clinically treat patients in the most scientific manner. My colleague Kuldev Singh, MD, who is a glaucoma specialist has said, “This term [randomized, controlled] allows the investigator to disarm the novice scientific critic, while impugning lesser prospective and all retrospective studies, not to mention case series and reports.” The randomized, controlled study is at the top of the food chain.
A case example of using low-level evidence-based medicine upon which to base treatment decisions is that of bevacizumab (Avastin, Genentech) for treating AMD. In August 2005, there was one case report (level 5 evidence) demonstrating improvement on optical coherence tomography (OCT) for a patient nonresponsive to pegaptanib sodium (Macugen, Eyetech/Pfizer) for AMD in the published literature.11 Simultaneously, Philip Rosenfeld, MD, PhD, one of the authors of the aforementioned case report, presented a paper (level 4 evidence) at the American Society of Retina Specialists in Montreal on a series of patients with exudative AMD who benefited from intravitreal bevacizumab. Clearly, the “bevacizumab for AMD” era was ushered in using the least convincing type of evidence.
Unlike bevacizumab, ranibizumab (Lucentis, Genentech) was subject to two phase 3 randomized, controlled clinical trials sponsored by industry (MARINA ANCHOR) that resulted in FDA approval. The extent to which the efficacy and safety of ranibizumab has been scrutinized is to the highest level.
But can you have a randomized, controlled trial for every disease and treatment? Paul Lichter, MD, said, “Authors of case reports, retrospective studies, and other manuscripts covering the gamut of imperfect clinical projects often conclude their papers by calling for a randomized, controlled, collaborative clinical trial. While I have no idea how many times such statements are made, there is no question that these pronouncements are abundantly more frequent then the clinical trials that result from them.”
CRITERIA FOR CONDUCTING A LEVEL 1 CLINICAL TRIAL
Clearly, a level 1 clinical trial cannot be conducted for every clinical situation. My four criteria for conducting a randomized, controlled clinical trial include the following:
* The disease must represent a significant health problem. An example of what can be called an questionable effort is in 1993 when the Canadian Ophthalmology Study Group conducted a multicenter randomized, controlled clinical trial to compare the argon green vs krypton red laser for choroidal neovascularization (CNV) in AMD.12 The comparison of these lasers was not a burning issue for the health care system.
* There must be scientific plausibility of benefit. In other words, there has to be some biologic basis for believing that a treatment works. An example from the AMD literature is subfoveal laser for CNV.13 There was no basis to suggest that applying laser to a patient’s fovea would be beneficial.
* A plausible, biologic benefit must exist. In other words, the early data on a new treatment should suggest the possibility of benefit. A good example of this is the Submacular Surgery Trials in AMD where early pilot data did not show any benefit to submacular surgery over laser photocoagulation.14 The eventual the long-term data supported this conclusion.
* Sufficient numbers of patients must be enrolled. If a study cannot recruit enough patients, it will not succeed. For example, it was almost impossible to recruit patients into the Macular Translocation clinical trial because they were randomized to either photodynamic therapy—a relatively painless 15-minute office-based laser procedure— or to macular translocation, which had a 25% complication rate at the time they were trying to enroll.15
The clinical trials’ registry, www.clinicaltrials.gov, currently lists 530 clinical trials for the treatment of AMD. Of those 200 trials are open and actively recruiting patients. Eighty-seven of these are randomized and controlled. Those of us in the field of ophthalmology and the subspecialty of retina are fortunate to be part of a profession that is committed to providing the best scientific evidence for its members. We have a long, proud history of practicing evidence-based medicine and performing randomized clinical trials in our field.
NON-INFERIOR CLINICAL TRIALS
There are basically three types of trial design: superiority, equivalence, and non-inferiority. The Comparisons of Age- Related Macular Degeneration Treatments Trials (CATT) is a non-inferiority trial comparing intravitreal ranibizumab to intravitreal bevacizumab. The margin of non-inferiority must be pre-specified in the design protocol to construct a two-sided, 95% confidence interval (CI) to determine the true difference between the agents. To be able to declare bevacizumab non-inferior, that interval must lay entirely on the positive side of the non-inferior margin.
Figure 3 helps illustrate how the results of a non-inferiority trial are interpreted. Applied to the CATT, if proved non-inferior, bevacizumab is either almost as good as, equivalent to, or better than ranibizumab. If bevacizumab fails non-inferiority then it is either equivalent, almost as good as, or inferior to ranibizumab. All of those possibilities exist.
The major criteria for non-inferiority clinical trials are:
1) historical evidence that the reference drug works (ie, MARINA and ANCHOR);
2) trial design must be the same as the reference trial (ie, the CATT has same design as MARINA and ANCHOR);
3) trial conduct must be the same (ie, many of the clinical sites from MARINA and ANCHOR are also sites for the CATT);
4) the non-inferior margin (minus delta) must be acceptable (ie, six letters for the CATT).
In addition to the CATT, there are two other non-inferiority trials in AMD: HARBOR (A Study of Ranibizumab Administered Monthly or on an As-Needed Basis in Patients With Subfoveal Neovascular Age-Related Macular Degeneration) and VIEW I (VEGF Trap-Eye: Investigation of Efficacy and Safety in Wet AMD). These are both similar to MARINA and ANCHOR in historical evidence, trial design and trial conduct, and have an acceptable non-inferior margin.
SUMMARY
The best way to practice evidence-based medicine is with phase 3, randomized, and controlled trials. The requirements for level 1 clinical trials do not necessarily constitute a “cookbook” for successful trials; rather, they provide guidelines for those who are designing and participating in clinical trials.
Finally, evidence alone is never sufficient information to make a clinical decision—there are many factors to be taken under consideration. When treating our patients, we consider several factors including a patient’s values, socio-economic status, and age; however we should rely on three main components: our years of clinical experience, the patient’s particular circumstances, and what we have learned from evidence-based medicine.
1. Friedman DS, O’Colmain BJ, Muñoz B, et al; The Eye Diseases Prevalence Research Group. Prevalence of age-related macular degeneration in the United States. Archives of Ophthalmology. 2004;122:564-572.
2. No authors listed. Submacular surgery trials randomized pilot trial of laser photocoagulation versus surgery for recurrent choroidal neovascularization secondary to age-related macular degeneration: II. Quality of life outcomes submacular surgery trials pilot study report number 2. Am J Ophthalmol. 2000;130(4):408-418.
3. National Institute of Diabetes and Digestive and Kidney Diseases. National Diabetes Statistics Fact Sheet: General Information and National Estimates on Diabetes in the United States. Bethesda, MD, US Department of Health and Human Services, National Institutes of Health, 2003.
4. King H, Rewers M. Global estimates for prevalence of diabetes mellitus and impaired glucose tolerance in adults: WHO Ad Hoc Diabetes Reporting Group. Diabetes Care. 1993;16:157–177.
5. Beaver Dam Eye Study.
6. Hogan P, Dall T, Nikolov P; American Diabetes Association. Economic costs of diabetes in the US in 2002. Diabetes Care. 2003;26(3):917-932.
7. Klein R, Klein BE, Moss SE, Linton KL. Beaver Dam Eye Study. Retinopathy in adults with newly discovered and previously diagnosed diabetes mellitus. Ophthalmology. 1992;99(1):58-62.
8. National Heart Lung and Blood Institute. Heart attack. Available at http://www.nhlbi.nih.gov/health/dci/Diseases/HeartAttack/HeartAttack_WhatIs.html.
9. Thom T, Haase N, Rosamond W, et al; American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics-2006 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Committee. Circulation. 2006;113:85-151.
10. Holekamp N. Arch Ophthalmol. In press.
11. Rosenfeld PJ, Moshfeghi AA, Puliafito CA. Optical coherence tomography findings after an intravitreal injection of bevacizumab (avastin) for neovascular age-related macular degeneration. Ophthalmic Surg Lasers Imaging. 2005;36(4):331-335.
12. The Canadian Ophthalmology Study Group. Argon green vs krypton red laser photocoagulation of extrafoveal choroidal neovascular lesions. One-year results in age-related macular degeneration. Arch Ophthalmol. 1993;111:181-185.
13. Macular Photocoagulation Study Group. Visual outcome after laser photo- coagulation for subfoveal neovascularization secondary to age-related macular degeneration. The influence of initial lesion size and initial visual acuity. Arch Ophthalmol. 1994;112:480–488.
14. Bressler NM, Bressler SB, Hawkins BS, Marsh MJ, Sternberg P Jr, Thomas MA; Submacular Surgery Trials Pilot Study Investigators. Submacular surgery trials randomized pilot trial of laser photocoagulation versus surgery for recurrent choroidal neovascularization secondary to age-related macular degeneration: I. Ophthalmic outcomes submacular surgery trials pilot study report number 1. Am J Ophthalmol. 2000;130(4):387-407.
15. Hawkins BS, Bressler NM, Miskala PH, et al; Submacular Surgery Trials (SST) Research Group. Surgery for subfoveal choroidal neovascularization in age-related macular degeneration: ophthalmic findings: SST report no. 11. Ophthalmology. 2004;111(11):1967-1980.
Monday, August 9, 2010
Retinitis pigmentosa treatment
As human beings, there is very little more universally feared than the dark, and few disabilities more frightening than blindness which would leave us trapped in it. Retinitis pigmentosa is a condition which, to many people, might sound like a nightmare. Retinitis pigmentosa refers to a group of genetic conditions in which the eye progressively degenerates over time. The first symptoms of retinitis pigmentosa are night blindness. This night blindness worsens over time, eventually developing into tunnel vision which little by little narrows the sufferer’s peripheral vision until finally they become legally – and perhaps totally – blind.
Progression is different in each case of retinitis pigmentosa. The night blindness phase of the disease can proceed tunnel vision by years or even decades, and many people with retinitis pigmentosa do not legally go blind until their forties or fifties. Some never retain some level of vision throughout their lives. At the same time, others may go blind as early as during childhood.
Retinitis pigmentosa diagnosis come as a fearful shock to some people, which is why retinitis pigmentosa treatments are so important.
Since time out of mind, people have struggled to treat the diseases around them. They have relied on everything from superstition, prayer, spells and religious chants to herbal remedies, surgeries and medicines, some of which are still in use today. Unfortunately for people before the modern era, there was very little to be done for loss of sight. Our ancestors had very few options in terms of treatment for retinitis pigmentosa. Retinitis pigmentosa is caused by abnormalities in the receptors in the eye, the rods and cones which allow us to see color, light and movement. As these abnormalities increase over time, the sufferer’s eyesight diminishes. There was very little for even our grandfathers and grandmothers to do when faced with this sort of disease. It has only been recently that our understanding of how the eye works, our understanding of how the body as a whole operates, and our technology has reached a point where retinitis pigmentosa treatments have become something of a reality and moved out of the realms of witchcraft and hope.
Retinitis pigmentosa treatments are still relatively few. There is no true cure for retinitis pigmentosa, only treatments which may help to slow the progression of this degenerative disease.
Among the first treatment options for people diagnosed with retinitis pigmentosa are medications and supplements. For example, vitamin A therapies can support eye health and slow the progression of this disease. People who receive these should have their liver enzymes checked annually, since in too great of doses, vitamin A can become toxic to the system. Other retinitis pigmentosa treatment options include omega-3 polyunsaturated fatty acid and antioxidant, docosahexaenoic acid, acetazolamide, lutein, and calcium blockers.
In the event that medication proves an ineffective retinitis pigmentosa treatment, there are also surgical treatments to consider. What kind of surgical options a patient may have for their retinitis pigmentosa treatment depends on many factors, as the progression of the disease varies greatly from person to person, and as the disease is associated with a number of other genetic and structural conditions. For some people, partial retinal transplants can be a useful retinitis pigmentosa treatment. The possibility of a retinal prosthetics
have also been under consideration for several years now. While there are currently no prosthetics available for clinical use as retinitis pigmentosa treatment, they may present a promising future for those with this degenerative disease.
Since retinitis pigmentosa is a genetic disorder, it should not be surprising that when considering retinitis pigmentosa treatments, speculation might turn to the possibilities of gene therapy and stem cell research. These treatments are, as yet, still in the research and investigation phases, but may well represent the future of retinitis pigmentosa treatment.
Progression is different in each case of retinitis pigmentosa. The night blindness phase of the disease can proceed tunnel vision by years or even decades, and many people with retinitis pigmentosa do not legally go blind until their forties or fifties. Some never retain some level of vision throughout their lives. At the same time, others may go blind as early as during childhood.
Retinitis pigmentosa diagnosis come as a fearful shock to some people, which is why retinitis pigmentosa treatments are so important.
Since time out of mind, people have struggled to treat the diseases around them. They have relied on everything from superstition, prayer, spells and religious chants to herbal remedies, surgeries and medicines, some of which are still in use today. Unfortunately for people before the modern era, there was very little to be done for loss of sight. Our ancestors had very few options in terms of treatment for retinitis pigmentosa. Retinitis pigmentosa is caused by abnormalities in the receptors in the eye, the rods and cones which allow us to see color, light and movement. As these abnormalities increase over time, the sufferer’s eyesight diminishes. There was very little for even our grandfathers and grandmothers to do when faced with this sort of disease. It has only been recently that our understanding of how the eye works, our understanding of how the body as a whole operates, and our technology has reached a point where retinitis pigmentosa treatments have become something of a reality and moved out of the realms of witchcraft and hope.
Retinitis pigmentosa treatments are still relatively few. There is no true cure for retinitis pigmentosa, only treatments which may help to slow the progression of this degenerative disease.
Among the first treatment options for people diagnosed with retinitis pigmentosa are medications and supplements. For example, vitamin A therapies can support eye health and slow the progression of this disease. People who receive these should have their liver enzymes checked annually, since in too great of doses, vitamin A can become toxic to the system. Other retinitis pigmentosa treatment options include omega-3 polyunsaturated fatty acid and antioxidant, docosahexaenoic acid, acetazolamide, lutein, and calcium blockers.
In the event that medication proves an ineffective retinitis pigmentosa treatment, there are also surgical treatments to consider. What kind of surgical options a patient may have for their retinitis pigmentosa treatment depends on many factors, as the progression of the disease varies greatly from person to person, and as the disease is associated with a number of other genetic and structural conditions. For some people, partial retinal transplants can be a useful retinitis pigmentosa treatment. The possibility of a retinal prosthetics
have also been under consideration for several years now. While there are currently no prosthetics available for clinical use as retinitis pigmentosa treatment, they may present a promising future for those with this degenerative disease.
Since retinitis pigmentosa is a genetic disorder, it should not be surprising that when considering retinitis pigmentosa treatments, speculation might turn to the possibilities of gene therapy and stem cell research. These treatments are, as yet, still in the research and investigation phases, but may well represent the future of retinitis pigmentosa treatment.
Monday, July 26, 2010
Commencement of CABERNET clinical trial
NeoVista, Inc announced the official commencement of the CABERNET (Cnv Secondary Amd Treated with BEta RadiatioN Epiretinal Therapy) clinical trial for the treatment of subfoveal choroidal neovascularization associated with wet age-related macular degeneration (AMD). Neovascular AMD is the leading cause of irreparable blindness in the elderly population, afflicting over 200,000 individuals each year in the U.S.
Dr. Nelson Sabates, Professor and Chairman, Department of Ophthalmology, University of Missouri-Kansas City (UMKC)/Truman Medical Centers and Director of Vision Research Center, University of Missouri-Kansas City at Truman Medical Centers performed the procedure on the first patient enrolled in the CABERNET study. When asked for initial feedback on the procedure, Dr. Sabates commented, "The procedure was no different than performing a common vitrectomy and the Epi-Rad device allowed me to deliver a well focused dose of radiation to the lesion. Treating neovascular AMD using a multi-faceted approach like the use of radiation and anti-VEGF therapy may well be the next frontier in combating this sight threatening disease."
The CABERNET clinical trial will involve clinical sites in the United States, Europe, Israel, and South America. The CABERNET trial protocol is divided into two treatment arms - investigational and control.
The investigational treatment arm consists of concomitant delivery of Beta radiation, via the proprietary NeoVista technology (Epi-Rad90™), and an FDA approved anti-VEGF agent. The investigational treatment is administered during an outpatient surgical procedure and delivers Beta radiation directly to the area of the retina that has been compromised by the disease. An injection of the anti-VEGF agent is administered at the time of surgery with one additional injection administered 30 days after surgery. The control arm is utilizing the FDA approved anti-VEGF agent alone.
The surgery was performed in collaboration with, Saint Lukes Hospital in Kansas City. Dr. Terry J. Wall, J.D., M.D. of the Saint Lukes Cancer Institute was the attending radiation oncologist involved with the procedure.
"This is a very good day for NeoVista employees and the investors who are supporting our work," stated John N. Hendrick, President and CEO of NeoVista. "More importantly, it is a potential harbinger of hope for those suffering from wet AMD." We remain optimistic that our treatment approach will provide maximum benefit to this patient population."
Dr. Nelson Sabates, Professor and Chairman, Department of Ophthalmology, University of Missouri-Kansas City (UMKC)/Truman Medical Centers and Director of Vision Research Center, University of Missouri-Kansas City at Truman Medical Centers performed the procedure on the first patient enrolled in the CABERNET study. When asked for initial feedback on the procedure, Dr. Sabates commented, "The procedure was no different than performing a common vitrectomy and the Epi-Rad device allowed me to deliver a well focused dose of radiation to the lesion. Treating neovascular AMD using a multi-faceted approach like the use of radiation and anti-VEGF therapy may well be the next frontier in combating this sight threatening disease."
The CABERNET clinical trial will involve clinical sites in the United States, Europe, Israel, and South America. The CABERNET trial protocol is divided into two treatment arms - investigational and control.
The investigational treatment arm consists of concomitant delivery of Beta radiation, via the proprietary NeoVista technology (Epi-Rad90™), and an FDA approved anti-VEGF agent. The investigational treatment is administered during an outpatient surgical procedure and delivers Beta radiation directly to the area of the retina that has been compromised by the disease. An injection of the anti-VEGF agent is administered at the time of surgery with one additional injection administered 30 days after surgery. The control arm is utilizing the FDA approved anti-VEGF agent alone.
The surgery was performed in collaboration with, Saint Lukes Hospital in Kansas City. Dr. Terry J. Wall, J.D., M.D. of the Saint Lukes Cancer Institute was the attending radiation oncologist involved with the procedure.
"This is a very good day for NeoVista employees and the investors who are supporting our work," stated John N. Hendrick, President and CEO of NeoVista. "More importantly, it is a potential harbinger of hope for those suffering from wet AMD." We remain optimistic that our treatment approach will provide maximum benefit to this patient population."
Treatment for Cataracts/ other eye diseases
What is a cataract?
There is only one known treatment for cataracts - surgery! A cataract needs to be removed only when vision loss interferes with your everyday activities, or the things you like to do such as driving, reading, sewing, playing golf or watching TV . You and your eye care professional can make this decision together. Once you understand the benefits and risks of surgery, you can make an informed decision about whether cataract surgery is right for you. In most cases, delaying cataract surgery will not cause long-term damage to your eye or make the surgery more difficult. You do not have to rush into surgery.
Additionally, Medicare and most commercial insurance carriers require that best corrected vision be reduced to some level (often 20/50 visual acuity) before they will approve the surgery for payment.
Sometimes a cataract should be removed even if it does not cause problems with your vision. For example, a cataract should be removed if it prevents examination or treatment of another eye problem, such as age-related macular degeneration or diabetic retinopathy.
If you choose surgery, your optometrist will refer you to an ophthalmic surgeon to remove the cataract. This is a very definite advantage over choosing an eye surgeon out of the phone book or from your friends because your doctor knows firsthand the quality of the cataract surgery performed by local eye surgeons. Because they work with the eye surgeons and usually perform some or all of the post-op care they truly know where to refer you for the best possible outcome. If you have cataracts in both eyes that require surgery, the surgery will be performed on each eye at separate times, usually four to eight weeks apart.
As with any surgery, cataract surgery poses risks, such as infection and bleeding. Before cataract surgery, your doctor may ask you to temporarily stop taking certain medications that increase the risk of bleeding during surgery. After surgery, you must keep your eye clean, wash your hands before touching your eye, and use the prescribed medications to help minimize the risk of infection. Serious infection can result in loss of vision. Talk to your eye care professional about these risks. Make sure cataract surgery is right for you.
Cataract surgery slightly increases your risk of retinal detachment. Other eye disorders, such as high myopia (nearsightedness), can further increase your risk of retinal detachment after cataract surgery. One sign of a retinal detachment is a sudden increase in flashes or floaters. Floaters are little "cobwebs" or specks that seem to float about in your field of vision. If you notice a sudden increase in floaters or flashes, see an eye care professional immediately. A retinal detachment is a medical emergency. If necessary, go to an emergency service or hospital. Your eye should be examined by a retinal specialist as soon as possible. A retinal detachment causes no pain. Early treatment for retinal detachment often can prevent permanent loss of vision. The longer the retina stays detached, the less likely you will regain good vision once you are treated. Even if you are treated promptly, some vision may be lost.
There is only one known treatment for cataracts - surgery! A cataract needs to be removed only when vision loss interferes with your everyday activities, or the things you like to do such as driving, reading, sewing, playing golf or watching TV . You and your eye care professional can make this decision together. Once you understand the benefits and risks of surgery, you can make an informed decision about whether cataract surgery is right for you. In most cases, delaying cataract surgery will not cause long-term damage to your eye or make the surgery more difficult. You do not have to rush into surgery.
Additionally, Medicare and most commercial insurance carriers require that best corrected vision be reduced to some level (often 20/50 visual acuity) before they will approve the surgery for payment.
Sometimes a cataract should be removed even if it does not cause problems with your vision. For example, a cataract should be removed if it prevents examination or treatment of another eye problem, such as age-related macular degeneration or diabetic retinopathy.
If you choose surgery, your optometrist will refer you to an ophthalmic surgeon to remove the cataract. This is a very definite advantage over choosing an eye surgeon out of the phone book or from your friends because your doctor knows firsthand the quality of the cataract surgery performed by local eye surgeons. Because they work with the eye surgeons and usually perform some or all of the post-op care they truly know where to refer you for the best possible outcome. If you have cataracts in both eyes that require surgery, the surgery will be performed on each eye at separate times, usually four to eight weeks apart.
As with any surgery, cataract surgery poses risks, such as infection and bleeding. Before cataract surgery, your doctor may ask you to temporarily stop taking certain medications that increase the risk of bleeding during surgery. After surgery, you must keep your eye clean, wash your hands before touching your eye, and use the prescribed medications to help minimize the risk of infection. Serious infection can result in loss of vision. Talk to your eye care professional about these risks. Make sure cataract surgery is right for you.
Cataract surgery slightly increases your risk of retinal detachment. Other eye disorders, such as high myopia (nearsightedness), can further increase your risk of retinal detachment after cataract surgery. One sign of a retinal detachment is a sudden increase in flashes or floaters. Floaters are little "cobwebs" or specks that seem to float about in your field of vision. If you notice a sudden increase in floaters or flashes, see an eye care professional immediately. A retinal detachment is a medical emergency. If necessary, go to an emergency service or hospital. Your eye should be examined by a retinal specialist as soon as possible. A retinal detachment causes no pain. Early treatment for retinal detachment often can prevent permanent loss of vision. The longer the retina stays detached, the less likely you will regain good vision once you are treated. Even if you are treated promptly, some vision may be lost.
Monday, July 19, 2010
Foveal Macular Edema Treatments
Located in the foveal region of the retina, the macula is an important part of the visual system, responsible for clear central vision. A damaged macula means distorted vision when looking at objects straight ahead. Macular edema, one type of damage, occurs when fluid accumulates in the tissue under the macula. Causes of edema include ocular inflammation and, more commonly, complications from uncontrolled diabetes. Prompt treatment is crucial to preserving vision when macular edema occurs.
Laser Treatment
According to the Mayo Clinic, macular edema is the leading cause of decreased vision in patients with early diabetic eye complications, also called background diabetic retinopathy. Uncontrolled diabetes leads to leakage of blood vessels in the back of the eye. Fluids, such as blood and fatty lipid material called exudates, can then accumulate. This can lead to numerous complications, including swelling under the macula tissue. When this occurs, clinically significant macula edema requires treatment with a focal laser procedure, also called focal laser photocoagulation. Laser light focused on the macula targets the leaky vessels, resulting in laser scars or burns that help reduce further leakage and the amount of fluid accumulated. If laser treatment for both eyes is necessary, the treatments are usually scheduled a few weeks apart. Focal laser photocoagulation is the mainstay treatment for macular edema caused by diabetic retinopathy and, according to the National Eye Institute, reduces the chance for vision loss by 50 percent.
Anti-inflammatory Drugs
Macular edema can result from retinal inflammation. It often follows procedures such as cataract surgery. In this type of edema, cyst-like pockets of fluid build up in the macular region--hence its name cystoid macular edema--and the reason for its development is unknown. Often, steroidal anti-inflammatory eyedrops are prescribed to treat cystoid macular edema. An injection of steroids--such as cortisone--into the eye can be necessary in cases of more severe edema. According to the University of Michigan, injecting steroids intraocularly for macular edema caused by diabetes is an emerging treatment option. Repeat injections are often necessary.
Vitrectomy
The vitreous is the large, gel-like area that makes up a bulk of the back of the eye. It comes in contact with the retina and macular tissue. Sometimes tugging of the macula by the vitreous gel can lead to macular edema. When this occurs, it's recommended to have surgery to remove the vitreous gel. This procedure is called a vitrectomy. A vitrectomy is also performed when macular edema and other complications caused by diabetes result in significant blood accumulation in the vitreous. This procedure is usually recommended for advanced diabetic cases.
Preventive Care
The most serious type of macular edema is connected to diabetic retinopathy, because there is a high risk for vision loss. Therefore, doctors strongly recommend control and care of blood sugar through diet, exercise and medication. Other preventive measures include annual eye exams and controlling other diseases such as high blood pressure and high cholesterol. The National Eye Institute reports that macula edema can often occur without symptoms of blur, so preventive care is essential to detecting it before lasting damage can occur.
Laser Treatment
According to the Mayo Clinic, macular edema is the leading cause of decreased vision in patients with early diabetic eye complications, also called background diabetic retinopathy. Uncontrolled diabetes leads to leakage of blood vessels in the back of the eye. Fluids, such as blood and fatty lipid material called exudates, can then accumulate. This can lead to numerous complications, including swelling under the macula tissue. When this occurs, clinically significant macula edema requires treatment with a focal laser procedure, also called focal laser photocoagulation. Laser light focused on the macula targets the leaky vessels, resulting in laser scars or burns that help reduce further leakage and the amount of fluid accumulated. If laser treatment for both eyes is necessary, the treatments are usually scheduled a few weeks apart. Focal laser photocoagulation is the mainstay treatment for macular edema caused by diabetic retinopathy and, according to the National Eye Institute, reduces the chance for vision loss by 50 percent.
Anti-inflammatory Drugs
Macular edema can result from retinal inflammation. It often follows procedures such as cataract surgery. In this type of edema, cyst-like pockets of fluid build up in the macular region--hence its name cystoid macular edema--and the reason for its development is unknown. Often, steroidal anti-inflammatory eyedrops are prescribed to treat cystoid macular edema. An injection of steroids--such as cortisone--into the eye can be necessary in cases of more severe edema. According to the University of Michigan, injecting steroids intraocularly for macular edema caused by diabetes is an emerging treatment option. Repeat injections are often necessary.
Vitrectomy
The vitreous is the large, gel-like area that makes up a bulk of the back of the eye. It comes in contact with the retina and macular tissue. Sometimes tugging of the macula by the vitreous gel can lead to macular edema. When this occurs, it's recommended to have surgery to remove the vitreous gel. This procedure is called a vitrectomy. A vitrectomy is also performed when macular edema and other complications caused by diabetes result in significant blood accumulation in the vitreous. This procedure is usually recommended for advanced diabetic cases.
Preventive Care
The most serious type of macular edema is connected to diabetic retinopathy, because there is a high risk for vision loss. Therefore, doctors strongly recommend control and care of blood sugar through diet, exercise and medication. Other preventive measures include annual eye exams and controlling other diseases such as high blood pressure and high cholesterol. The National Eye Institute reports that macula edema can often occur without symptoms of blur, so preventive care is essential to detecting it before lasting damage can occur.
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