Posted by: Clemson Eye in News
Clemson Eye News, July 2014
Diabetes is a group of metabolic diseases that result in a person having high blood sugar. Diabetes affects 26 million Americans today compared to 6 million in 1985. That’s an exponential increase. Today, over 8% of all Americans and almost 30% over age 651 have diabetes.
Untreated, diabetes can cause multiple complications, potentially damaging many organ systems primarily through small blood vessel disease. Serious long-term complications include heart disease, kidney failure and damage to the eyes.
Diabetic retinopathy is the leading cause of new cases of blindness in patients ages 20-74.
Types of Diabetes
Type I Diabetes results when the body fails to produce insulin. It was previously referred to as insulin-dependent diabetes mellitus or “juvenile diabetes.”
Type II Diabetes results from insulin resistance and deficiency. This form was previously referred to as non-insulin-dependent diabetes mellitus or “adult-onset diabetes.”
Type I accounts for 5% of all cases in adults, while Type II encompasses the lion’s share with 90-95% of all cases. The remaining 1-5% includes specific genetic conditions, pregnancy, medications, surgery, infections, and other illnesses.
More Obesity, More Diabetes
In recent years, the incidence of Type II Diabetes has grown significantly, driven by higher rates of obesity. In fact, 35% of adults and 50% of seniors are pre-diabetic based on A1C testing, the primary test used for diabetes measure-ment, management and research.
The Center for Disease Control and Prevention (CDC) publishes obesity and diabetes prevalence maps, which pro-vide a visual of this growing epidemic.2
More Obesity, More Diabetes
In recent years, the incidence of Type II Diabetes has grown significantly, driven by higher rates of obesity. In fact, 35% of adults and 50% of seniors are pre-diabetic based on A1C testing, the primary test used for diabetes measure-ment, management and research.
The Center for Disease Control and Prevention (CDC) publishes obesity and diabetes prevalence maps, which pro-vide a visual of this growing epidemic.2
Here in the Southeast, we lead the trend with increasing rates of obesity and diabetes starting in Mississippi, then Alabama, and spreading across the region. Ten percent of adult South Carolinians have diabetes.3
Of those with Type II Diabetes, 55% have a Body Mass Index of more than 30, which is the definition of obesity. Certain ethnicities have a higher risk, with American Indians at greatest risk followed by non-Hispanic Blacks.1 Fortunately for diabetic patients, risks of amputation, end-stage renal disease, and hyperglycemic death have decreased in recent decades.3 None-theless, the annual costs of diabetes are approaching $200 billion in the United States.
Diabetic Eye Disease
High sugar or glucose levels cause damage to the blood vessels in the retina, as well other organs. After being exposed to high sugar levels for a long time, abnormal blood vessels called microaneurysms can form. Leakage of fluid or blood into the retina can occur.
Leakage of fluid is the most common cause of vision loss in diabetics, but more severe bleeding and scarring can occur from even larger “nets” of abnormal blood vessels.
Diabetic Retinopathy can be categorized into non-proliferative and proliferative retinopathy. More than 4 million dia-betics over age 40 have retinopathy with 655,000 having the more severe proliferative complications.1
Treatments
Treatments start with diagnosis. Unfortunately, only 63% of diabetics receive their recommended yearly eye exam3. Most diabetic adults (65%) can be helped with eyeglasses. Traditional focal/grid laser and pan-retinal lasers can reduce the risk of severe vision loss
by 50-60%.
Diabetic macular edema, the earliest complication affecting vision and leading cause of visual loss, has shifted recently towards injection therapies. Studies have shown superiority of visual outcomes with anti-VEGF (vascular endothelial growth factor) injections ver-sus traditional laser treatments.4The most recent studies show 6 letters of vision gained versus 1 letter lost with laser treatments (note that untreated patients would have lost more).5
Practically, many specialists now use a combination of therapies to decrease the frequency of injections needed.6 In addition, improvements in macular laser treatments in recent years decrease the light intensities and durations. The most advanced stages of proliferative retin-opathy are still treated with pan-retinal laser. However, the same anti-VEGF injections are frequently used in com-bination for their more rapid resolution of new blood vessels, which can cause blinding hemorrhages or aggressive neovascular glaucoma.
When bleeding or glaucoma is severe, a sutureless vitrectomy is often performed to clear blood for a more rapid return
of vision and to reduce risk of future bleeding by separating the vitreous gel from pulling on the abnormal vessels.
As the prevalence of diabetes continues to grow in our population, it is more important than ever for us as health care professionals to educate the public on the importance of regular eye exams, as well as nutrition and lifestyle. Diabetic eye disease and the vision loss caused by it are preventable, but only with a timely diagnosis and treatment.
Donald Glaser, MD, is a Clemson Eye ophthalmologist specializing in diabetic eye disease and comprehensive medical/surgical eye care.
1. National Diabetes Fact Sheet, 2011. Accessed 2014 from CDC website.
2. www.cdc.gov/diabetes/statistics/slides/maps_diabetesobesity_trends.pdf. (Available in images and Power Point formats as well on CDC site.)
3. Diabetes Report Card 2012. Accessed 2014 from CDC website.
4. A Randomized Trial to Assess Functional and Structural Effects of Ranibizumab versus Laser in Diabetic Macular Edema (the LUCIDATE Study). Comyn O, Sivaprasad S, Peto T, Neveu MM, Holder GE, Xing W, Bunce CV, Patel PJ, Egan CA, Bainbridge JW, Hykin PG. Am J Ophthalmol. 2014 May;157(5):960-970.e2. doi:10.1016 / j.ajo. 2014.02.019. Epub 2014 Feb 14.
5. Multiple studies under original ETDRS studies.
6. Retina 2014 meeting and ongoing studies in DRCR.net.
