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Clinical Questions In Managing Patients With Diabetic Eye Disease |
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Doctor Profile |
In 2002 the total economic cost of diabetes was estimated to be $132 billion, which translates to one in every ten healthcare dollars spent in the US.
Diabetes is the fifth deadliest disease in the US.
Nearly all patients who have Type 1 diabetes for about 20 years will have evidence of diabetic retinopathy.
Up to 21% of people with Type 2 diabetes have retinopathy when they are first diagnosed with diabetes, and most will eventually develop some degree of retinopathy.
In the United States, diabetes is responsible for 8% of legal blindness, making it the leading cause of new cases of blindness in adults 20-74 years of age. Each year 12,000 to 24,000 people lose their sight because of diabetes.
Glaucoma, cataract and corneal disease are more common in people with diabetes and contribute to the high rate of blindness.
Diabetic Retinopathy At The Molecular And Cellular Level
The retina is one of the most metabolically active organs in the body. Retinal pericytes and microvascular endothelial cells are lost early in the disease. In addition, thickening of the retinal basement membrane, similar to the changes seen in glomeruli, can lead to retinal capillary microaneurysms, excessive vascular permeability and increased activity of vasoproliferative substances such as VEGF and IGF-1. Progressive leakage of lipid and proteinaceous material leads to clinically evident macular edema and central visual loss. The initial stage of cell death and increased capillary permeability is followed by progressive microvascular obliteration, ischemic injury and unregulated angiogenesis. Neovascularization is the hallmark of Proliferative Diabetic Retinopathy (PDR) and can develop at the optic disc or elsewhere in the fundus. Untreated, neovascularization frequently leads to serious, sight-threatening complications of vitreous hemorrhage and traction retinal detachment.
Clinical Trials Guide Management Of Diabetic Retinopathy
Photocoagulation is the primary treatment for advanced retinopathy. Its efficacy was demonstrated in the Diabetic Retinopathy Study (DRS) in which 1758 diabetic patients with advanced retinopathy were randomly assigned to panretinal photocoagulation in one eye. The cumulative risk of developing severe visual loss was reduced by more than 50 percent in the treated eyes.
After panretinal photocoagulation became the standard of care in patients with high-risk features, attention was directed at earlier stages of the disease, which also frequently led to blindness. The Early Treatment Diabetic Retinopathy Study (ETDRS) randomly assigned 3711 patients with mild to severe nonproliferative or early proliferative retinopathy to photocoagulation in one eye and deferred therapy in the other eye. Focal laser photocoagulation for Diabetic Macular Edema (DME) was found to decrease the risk of visual loss by 50% in eyes with clinically significant macular edema. Early panretinal laser photocoagulation, however, was not felt to be required.