The most common eye disease among those with type 1 or type 2 diabetes is diabetic retinopathy and this book explains the disease, how it develops, and options for treatment. Affecting more than five million Americans, the disease is caused by damage to the tiny blood vessels of the retina as the result of uncontrolled blood sugars, and is a leading cause of blindness. Diabetic retinopathy cannot be cured, however the onset can be delayed and the risk of progression can be reduced by keeping tight controls on glucose levels and making the right lifestyle choices. This guide will help both patients and their families by covering such topics as symptoms, stages of the disease, how it is diagnosed, treatment options, ways to slow its progression, and lifestyle changes that lead to better glucose control.
The most common eye disease among those with type 1 or type 2 diabetes is diabetic retinopathy and this book explains the disease, how it develops, and options for treatment. Affecting more than five million Americans, the disease is caused by damage to the tiny blood vessels of the retina as the result of uncontrolled blood sugars, and is a leading cause of blindness. Diabetic retinopathy cannot be cured, however the onset can be delayed and the risk of progression can be reduced by keeping tight controls on glucose levels and making the right lifestyle choices. This guide will help both patients and their families by covering such topics as symptoms, stages of the disease, how it is diagnosed, treatment options, ways to slow its progression, and lifestyle changes that lead to better glucose control.
Diabetic Retinopathy: From Diagnosis to Treatment
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Overview
The most common eye disease among those with type 1 or type 2 diabetes is diabetic retinopathy and this book explains the disease, how it develops, and options for treatment. Affecting more than five million Americans, the disease is caused by damage to the tiny blood vessels of the retina as the result of uncontrolled blood sugars, and is a leading cause of blindness. Diabetic retinopathy cannot be cured, however the onset can be delayed and the risk of progression can be reduced by keeping tight controls on glucose levels and making the right lifestyle choices. This guide will help both patients and their families by covering such topics as symptoms, stages of the disease, how it is diagnosed, treatment options, ways to slow its progression, and lifestyle changes that lead to better glucose control.
Product Details
| ISBN-13: | 9781936374465 |
|---|---|
| Publisher: | Addicus Books |
| Publication date: | 03/01/2014 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 115 |
| File size: | 2 MB |
About the Author
Read an Excerpt
Diabetic Retinopathy
From Diagnosis to Treatment
By David S. Boyer, Homayoun Tabandeh
Addicus Books, Inc.
Copyright © 2014 David S. Boyer, M.D., and Homayoun Tabandeh, M.D.All rights reserved.
ISBN: 978-1-936374-46-5
CHAPTER 1
Diabetic Retinopathy: An Overview
If you have type 1 or type 2 diabetes, you are at risk for developing diabetic retinopathy. According to the National Eye Institute, between 40 and 45 percent of Americans with diabetes have some form of diabetic retinopathy, the most common eye condition linked to diabetes.
In the United States, the Centers for Disease Control and Prevention reports between 12,000 and 24,000 new cases of blindness each year due to diabetic retinopathy, making it the leading cause of vision loss among American adults between the ages of twenty and seventy-four. The Center also projects that by 2050, the number of Americans ages forty and older affected by diabetic retinopathy will grow from a current 5 million individuals to about 16 million. Although these statistics are alarming, you can prevent or delay damage to your vision by controlling your diabetes along with getting regular eye evaluations and treatment.
Defining Diabetic Retinopathy
Diabetic retinopathy is a disease of the retina caused by diabetes. It usually affects both eyes and occurs when uncontrolled blood sugar levels damage the small vessels of the retina, the light-sensitive tissue in the back of your eye. The retina is responsible for processing images that make vision possible. To produce clear, distortion-free vision, the retina must receive an abundant supply of oxygen and nutrients. If the blood vessels to the retina are damaged as a result of diabetes, the retina becomes deprived of essential nutrients and will not function correctly. The delicate retina tissue is gradually damaged, and images that you see may be blurred or otherwise distorted.
Diabetic retinopathy is a progressive disease — it worsens over time. Although some effects, such as blurriness and distortion, may be mild or short-term, other complications can cause severe, long-term vision loss.
Symptoms of Diabetic Retinopathy
Because diabetic retinopathy rarely causes pain, symptoms are not always apparent in the early stages. In fact, damage to your retina could be occurring long before you have noticeable signs. When symptoms do occur, they are often caused by retinopathy affecting the macula, the area of the retina responsible for central vision. Symptoms may include the following:
• blurred vision
• seeing dark spots or "floaters" (small specs in your field of vision)
• vision loss
• blind spots in your vision
It is important that you see your eye specialist as soon as possible if you have any such symptoms. Diabetic retinopathy cannot be cured, but with careful monitoring it can be diagnosed, treated, and controlled before it impairs your vision further.
Types of Diabetic Retinopathy
The main forms of diabetic retinopathy include nonproliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), diabetic macular edema, and advanced diabetic eye disease.
Nonproliferative Diabetic Retinopathy
Nonproliferative diabetic retinopathy is an early form of the disease in which symptoms might be nonexistent or mild. Damage results from injury to the capillaries, small blood vessels of your retina. With nonproliferative diabetic retinopathy, damage to the retina may occur in two ways. First, the tiny vessels weaken, and eventually leak blood and fluid into the retina. Second, blockage of small bloodvessel networks may result in areas of the retina becoming deprived of oxygen and nutrients. This leads to a cycle of more retinal tissue damage and more abnormal leakage from the blood vessels.
Eye specialists classify nonproliferative diabetic retinopathy as mild, moderate, or severe depending on the amount of retinal abnormalities they see during a retina examination. These stages of the disease are described in the text that follows.
Mild nonproliferative diabetic retinopathy. This phase occurs when retinal blood vessels first weaken and leak. Tiny bulges, known as microaneurysms, protrude from the vessel walls. At the same time, retinal hemorrhages, tiny "dots" or "blotches," leak from the capillaries into the retina while protein and lipid deposits, called hard exudates, form on the retina. They look like tiny waxy white or yellow flecks. Although an ophthalmologist can see these flecks during an eye examination, you may not notice any symptoms at this point, unless the center of your macula is involved.
Moderate nonproliferative diabetic retinopathy. This stage of retinopathy occurs as more hemorrhages and microaneurysms form. Small vessels that normally nourish the retina actually may become blocked or closed. These obstructions may cause a decrease in the supply of oxygen and nutrient-rich blood to the retina, particularly to the macula, in what is called retinal or macular ischemia. The oxygen loss prevents the macula from working correctly and causes vision problems.
Severe nonproliferative diabetic retinopathy. This stage is characterized by more extensive retinal hemorrhages, microaneurysms, dilation of blood vessels, and opening of blood vessels called "intraretinal microvascular abnormalities." Because many more retinal blood vessels are blocked or closed during this stage of nonproliferative diabetic retinopathy, larger areas of the retina are deprived of necessary oxygen and nutrients. In an attempt to reestablish the oxygen supply and nourishment, the retina produces special chemicals that trigger growth of new blood vessels. Increased production of these chemicals also causes the retinal blood vessels to leak more and build up fluid in the retina, particularly in the macula.
Proliferative Diabetic Retinopathy (PDR)
A more advanced form of the disease, proliferative diabetic retinopathy occurs when the retina is so deprived of oxygenated blood that abnormal blood vessels grow or proliferate to accommodate the loss (this is called retinal neovascularization). It would seem that this proliferation would be nature's healing response; however, the new vessels are so fragile that they may break and bleed, causing scarring that may lead to loss of vision. Proliferative diabetic retinopathy carries with it the same problems associated with nonproliferative diabetic retinopathy, such as diabetic macular edema, along with several others, including diabetic macular edema, vitreous hemorrhage, retinal detachment, and neovascular glaucoma.
Diabetic Macular Edema
Diabetic macular edema refers to swelling of the macula (central part of the retina) caused by a buildup of leakage from blood vessels. Macular edema leads to blurring and loss of central vision, and it is the most common cause of blindness among those with diabetic retinopathy. Macular edema may occur with proliferative diabetic retinopathy or with nonproliferative diabetic retinopathy.
Advanced Diabetic Eye Diseases
Vitreous Hemorrhage
A common complication of severe proliferative diabetic retinopathy, a vitreous hemorrhage refers to bleeding into the vitreous. As mentioned earlier, the vitreous is the clear gel that fills the space in the middle of the eye. It is situated between the lens in the front of the eye and the retina lining the back of the eye. There are normally no blood vessels within the vitreous gel.
Under normal circumstances, light rays pass through the vitreous to reach the retina. In proliferative diabetic retinopathy, however, fragile new vessels of the retina can rupture, clouding the once transparent vitreous gel with blood so those light rays cannot reach the retina. Although vitreous bleeding can cause vision problems, it usually does not trigger permanent vision loss. In many cases, proper treatment will restore vision.
Tractional Retinal Detachment
One of the most serious complications of proliferative diabetic retinopathy is a tractional retinal detachment. It occurs when scar tissue forms alongside new vessels. As the scarring shrinks and contracts, it pulls on the retina and its blood vessels. This contracting not only causes the vessels to bleed but also causes the retina to wrinkle. It may pull away from its normal position, tear, or completely detach. The wrinkling may distort your vision. If the macula or large retinal areas detach, you will likely experience greater vision loss. As a serious complication, tractional retinal detachment may require surgical correction to avoid progressive and permanent loss of vision.
Neovascular Glaucoma
Proliferative diabetic retinopathy is a risk factor for a severe type of glaucoma called neovascular glaucoma. This condition develops when new vessels growing over the iris block the normal flow of fluids away from the eye; this blockage causes severely elevated eye pressure. When the pressure inside the eye rises to higher levels, the optic nerve — which transfers visual information to the brain — is severely damaged. Symptoms of neovascular glaucoma include eye pain, redness, and loss of vision.
Risk Factors for Diabetic Retinopathy
There are many factors that can raise your risk for diabetic retinopathy. You will note, however, that many of these risk factors can be controlled.
Duration of Diabetes
The longer you have had poorly controlled blood glucose levels, the higher your risk for diabetic retinopathy. Most diabetic individuals develop eye problems over time, making duration of their diabetes one of the strongest predictors that they will develop this eye disease. Research has shown that nearly all type 1 diabetics and 60 percent of type 2 diabetics develop diabetic eye disease within the first two decades of their diabetes diagnosis.
The findings of the Wisconsin Epidemiological Study of Diabetic Retinopathy, which tracked complications in nearly 2,400 type 1 and type 2 diabetic individuals, supports the idea that the longer you have diabetes, the greater your chances for developing diabetic retinopathy. In the study, among younger-onset (type 1) diabetes patients alone, the prevalence of retinopathy was 8 percent at three years, 25 percent at five years, 60 percent at ten years, and 80 percent at fifteen years. By fifteen years, 25 percent of participants had advanced diabetic retinopathy.
According to the same study, up to 21 percent of type 2 diabetics have retinopathy when they're diagnosed with diabetes. Most patients develop some degree of it over time.
Poor Blood Glucose Control
In addition to the duration of your diabetes, controlling your blood glucose has a major bearing on your risk for diabetic retinopathy. Chronically high blood glucose levels, or hyperglycemia, damages your retinal vessels. The American Diabetes Association (ADA) recommends fasting glucose levels between 70 and 120 mg/dL and less than 180 mg/dL two hours after meals. The association also recommends a hemoglobin A1c (HA1c) of 7 percent or less. The hemoglobin A1c is a protein in red blood cells that bonds with blood sugars. Becasue red blood cells can live from 90 to 120 days, the hemoglobin A1c stays in the blood for that length of time. Accordingly, the HA1c provides a measurement of blood sugar control over the previous few months. This test tells doctors how well your treatment plan is working.
Defining Diabetes
Diabetes mellitus, or simply diabetes, is a group of metabolic diseases in which the body does not metabolize glucose properly, resulting in high blood sugar. Glucose is the most commonly found type of sugar in the body. Under normal circumstances a number of hormones help regulate the glucose metabolism, the most important being insulin.
Insulin helps body cells take up and process sugar in to energy. Insulin is produced by the pancreas, a small gland sandwiched between the spine and stomach. In diabetes, there is either a deficiency of insulin production or an increased resistance to its effects, resulting in high levels of blood glucose. The chronically elevated blood glucose damages various organs of the body including the eye, the kidney, the nerves, and the blood vessels throughout the body. There are many types of diabetes, the main ones are type 1 diabetes and type 2 diabetes.
Type 1 diabetes occurs when the pancreas does not produce enough insulin. It usually develops during childhood or adolescence; it can also occur in adults, however. About 10 percent of those with diabetes have type 1. This form was previously referred to as insulin-dependent diabetes mellitus or juvenile diabetes. Those with type 1 diabetes need to take insulin injections or receive infusions from an insulin pump, which is worn; the pump may be attached to a waistband, pocket, bra, garter belt, sock, or underwear. Once produced from cow and pig pancreases, today's insulin is made from genetically engineered bacteria and manufactured in a laboratory.
Type 2 diabetes is the most common type of diabetes, affecting about 90 percent of those with diabetes. It results from insulin resistance, a condition in which cells fail to use insulin efficiently. As a result, blood glucose levels rise. This form of the disease is often referred to as adult-onset diabetes. Many individuals take oral medication; others may require daily insulin injections.
Obesity
The more fatty tissue you have, the more resistant your cells are to insulin. Obesity increases your risk for diabetes as well as other serious conditions such as high cholesterol and high blood pressure. Estimates suggest that 65 percent of Americans are overweight, meaning they have a body mass index (BMI) of 25 to 29. Body mass index is a measurement of one's percentage of body fat — the ratio between one's weight and one's height.
Using BMI does have its drawbacks. The formula doesn't consider lean body mass, so a muscular, heavy person may have a high BMI but be in terrific shape. For the vast majority of the population, however, BMI remains the best overall indicator of obesity.
Lifestyle Choices
A sedentary lifestyle, especially if you are overweight, contributes to many diseases, including diabetes, heart disease, high blood pressure, and high cholesterol levels. On the other hand, physical exercise improves circulation, lowers blood sugars, and improves your body's use of insulin. This results in improved blood sugar levels. This benefit of increased sensitivity to insulin continues for hours after you stop exercising.
Exercise also promotes weight loss. A sedentary lifestyle contributes to insulin resistance, making it more difficult to keep weight off. Even light or moderate physical activity can help lower blood sugars.
Smoking is another major risk factor for developing diabetic retinopathy. Smoking also causes diabetic retinopathy to progress faster. The nicotine in tobacco not only contributes to higher blood pressure and higher cholesterol levels, but it also impairs insulin activity. Even though quitting smoking can be difficult, it is critical to heart health and diabetes control.
Unlike smoking, alcohol consumption doesn't have a direct influence on diabetic retinopathy. Yet, because it can affect diabetes control, drinking in excess can affect the health of your eyes. Your doctor can tell you what constitutes drinking in moderation.
High Cholesterol Levels
Diabetes puts you at risk for chronically high cholesterol or blood fats that promote the buildup of plaque in your arteries. Although the small vessels of the retina are too small for such buildup, uncontrolled cholesterol can contribute to macular edema and the development of hard exudates, the small yellow spots or lipid deposits that may form in the retina. Both conditions are associated with a higher risk of vision loss.
Doctors advise keeping "bad" or low-density cholesterol (LDLs) less than 70 mg/dL. "Good" cholesterol or high-density lipoproteins (HDLs) should be greater than 40 mg/dL in men and 50 mg/dL in women. Both men and women should strive for triglycerides, another type of fat, at levels less than 150 mg/dL.
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Excerpted from Diabetic Retinopathy by David S. Boyer, Homayoun Tabandeh. Copyright © 2014 David S. Boyer, M.D., and Homayoun Tabandeh, M.D.. Excerpted by permission of Addicus Books, Inc..
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
Contents
Acknowledgments,Introduction,
1 Diabetic Retinopathy: An Overview,
2 Getting a Diagnosis,
3 Treatment for Nonproliferative Diabetic Retinopathy,
4 Treatments for Proliferative Diabetic Retinopathy,
5 Reducing the Progression of Diabetic Retinopathy,
6 Coping with Vision Impairment,
Resources,
Glossary,
Index,
About the Authors,