Rising Rates of Diabetic Retinopathy Not Entirely Bad News
By A.Paul Chous, MA, OD, FAAO
About 1 in 3 people with diabetes has diabetic retinopathy, and 1 in 10 has severe retinopathy (proliferative retinopathy and/or diabetic macular edema) that threatens vision without prompt diagnosis and treatment. Rates of diabetic retinopathy in adults over the age of 40 in the United States have gone up 89% in the last ten years, based on analysis of evidence by the organization Prevent Blindness America in conjunction with the National Eye Institute. This is not surprising given increases in the number of Americans being diagnosed with diabetes (almost 2 million new cases per year), but it also reflects some other trends that warrant close attention by those of us in the diabetes community:
1. Detection of diabetic retinopathy has improved dramatically over the last 10 years. It is entirely possible, and likely, that retinopathy detection has increased as a function of both improved technology and increased visits to eye doctors (optometrists and ophthalmologists). Use of sophisticated retinal cameras with specialized filters that assist doctors in identifying early blood vessel damage due to diabetes has become common in many eye doctors' offices and allows us to scrutinize more of the back of the eye for subtle changes better than ever before. Optical coherence tomography (OCT), a form of optical ultrasound, allows eye doctors to see microscopic changes in the retina with incredible detail (see my previous dLife column, Pictures Worth a Thousand Words). Newer imaging systems will allow us to see early biochemical changes in the retina that presage the onset of diabetic retinopathy. All of these advances make detection better. If you don't detect a problem adequately, it will be under-diagnosed.
2. More patients with diabetes are getting dilated eye exams more often. In addition, many more patients with diabetes are getting eye examinations than ever before, both because primary care physicians are being required (by healthcare organizations and insurance companies) to ensure their diabetes patients have regular dilated eye exams (to meet quality care standards and save money associated with vision loss) and because patients are increasingly becoming educated about the importance of regular eye exams to prevent blindness. If you don't get a thorough eye examination on a routine basis, you won't be diagnosed with diabetic retinopathy, whether you have it or not.
Given the above points, it may be that rates of actual diabetic retinopathy (per 1000 diagnosed with diabetes, for example) may not have grown as much as it would appear, because eye doctors are better at detecting it and many patients who otherwise would have gone undiagnosed are now being diagnosed. This means earlier intervention and less risk of permanent vision loss.
3. The severity of retinopathy matters. It is very important to distinguish between retinopathy in general (ranging from mild to severe) and sight-threatening diabetic retinopathy (proliferative retinopathy and diabetic macular edema) that causes permanent visual disability or blindness. The fact is, most cases of diabetic retinopathy do not lead to severe vision loss because we have made so many advances in achieving better metabolic control (blood sugar, blood pressure, and lipids) that prevents mild retinopathy from progressing to severe retinopathy, and because treatments for severe retinopathy have improved tremendously.
If we live a long time, which patients with diabetes are increasingly doing, most of us with diabetes will develop some retinopathy. The key is to delay this as long as possible but, even more importantly, to prevent diabetic retinopathy from progressing to a stage that threatens our vision. I'll have more on this topic for you in my next dLife column.
For more information on diabetic eye disease, consult Dr. Chous' book Diabetic Eye Disease: Lessons From a Diabetic Eye Doctor, Fairwood Press, Seattle, 2003.
NOTE: The information is not intended to be a replacement or substitute for consultation with a qualified medical professional or for professional medical advice related to diabetes or another medical condition. Please contact your physician or medical professional with any questions and concerns about your medical condition.
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