Diabetic retinopathy (DR) is a leading cause of vision loss in the United States and occurs as a result of pathologic changes of the retinal vasculature. In 2005–2008, the estimated crude prevalence among Americans over the age of 40 with diabetes was 28.5 percent. Although the prevalence of vision-threatening DR is approximately 4.4 percent, the number of affected Americans 40 years or older is expected to triple from 1.2 million in 2005 to 3.4 million in 2050. The prevalence and severity of DR increases with the duration of diabetes; however, it is inversely correlated to glycemic and blood pressure control. Moderate vision loss is most commonly related to retinal leakage within the macula, while severe vision loss usually occurs as a result of neovascularization (proliferative diabetic retinopathy; PDR) with subsequent hemorrhage or fibrosis.
Early identification and treatment of DR is important since treatment is both cost-effective and reduces vision loss. The American Academy of Ophthalmologists, the American Optometric Association, and the American Diabetes Association recommend an annual dilated eye examination for all people with diabetes, and more frequent eye examinations for people with known DR. Other researchers argue that the frequency of examinations should be stratified to an individual’s risk of progression and vision loss.
The mainstay of DR treatment is aimed at reducing the risk of onset and limiting the progression of the disease. Therefore, retinal assessments should be performed on a regular basis to determine the presence and degree of DR, glycemic control should be optimized, and known risk factors such as blood pressure, dyslipidemia, elevated cholesterol, renal disease and abdominal obesity should be controlled. Direct ocular therapy should be prescribed when indicated, while vision rehabilitation and low vision aids should to be used to maximize vision if there is a loss.
Until recently, the primary treatment for DR has been focal or grid laser of the retina. Serial intravitreal injections of triamcinolone have been introduced as a treatment option as they have been shown to be effective at reducing diabetic macular edema (DME); however, their use is becoming less common due to significant adverse effects including elevated intraocular pressure and cataract formation. Ranibizumab and becvacizumab are being used with increasing frequency for the treatment of DME; however they have not yet been approved for use in this condition by the Food and Drug Administration. The recommended treatment of PDR remains panretinal photocoagulation with vitrectomy surgery performed when necessary. It is important to note that treatment of DR is not always aimed at restoration of pre-disease visual acuity, but rather at limiting further deterioration. Patients may report a decrease in visual acuity immediately after therapy, which may manifest in low initial perceptions of treatment satisfaction. However, results from the Early Treatment Diabetic Retinopathy Study demonstrate that early treatment with either panretinal photocoagulation or vitrectomy prevents long-term disability due to blindness.
Diabetic patients with retinopathy have reported that vision loss impacts multiple areas of well-being including: independence, mobility, leisure, and self-care. Additionally, DR has been found to impair functioning and overall health-related quality of life (HRQL).