Recommendations
General recommendations
* Optimal glycemic control can substantially reduce the risk and progression of diabetic retinopathy. (A)
* Optimal blood pressure control can reduce the risk and progression of diabetic retinopathy. (A)
* Aspirin therapy does not prevent retinopathy or increase the risks of hemorrhage. (A)
Screening
* Adults and adolescents with type 1 diabetes should have an initial dilated and comprehensive eye examination by an ophthalmologist or optometrist within 3??2 diabetes should have an initial dilated and comprehensive eye examination by an ophthalmologist or optometrist shortly after the diagnosis of diabetes. (B)
* Subsequent examinations for type 1 and type 2 diabetic patients should be repeated annually by an ophthalmologist or optometrist. Less frequent exams (every 2??DRS tested whether scatter (panretinal) photocoagulation surgery could reduce the risk of vision loss from PDR. Severe visual loss (i.e., best acuity of 5/200 or worse) was seen in 15.9% of untreated vs. 6.4% of treated eyes. The benefit was greatest among patients whose baseline evaluation revealed HRCs (chiefly disc neovascularization or vitreous hemorrhage with any retinal neovascularization). Of control eyes with HRCs, 26% progressed to severe visual loss vs. 11% of treated eyes. Given the risk of a modest loss of visual acuity and of contraction of visual field from panretinal laser surgery, such therapy has been primarily recommended for eyes approaching or reaching HRCs.
The ETDRS established the benefit of focal laser photocoagulation surgery in eyes with macular edema, particularly those with clinically significant macular edema. In patients with clinically significant macular edema after 2 years, 20% of untreated eyes had a doubling of the visual angle (e.g., 20/50 to 20/100) compared with 8% of treated eyes. Other results from the ETDRS indicate that, provided careful follow-up can be maintained, scatter photocoagulation surgery is not recommended for eyes with mild or moderate NPDR. When retinopathy is more severe, scatter photocoagulation surgery should be considered, and usually should not be delayed, if the eye has reached the high-risk proliferative stage. In older-onset patients with severe NPDR or less-than-high-risk PDR, the risk of severe visual loss and vitrectomy is reduced 50% by laser photocoagulation surgery at these earlier stages.
Laser photocoagulation surgery in both the DRS and the ETDRS was beneficial in reducing the risk of further visual loss, but generally not beneficial in reversing already diminished acuity. This preventive effect and the fact that patients with PDR or macular edema may be asymptomatic provide strong support for a screening program to detect diabetic retinopathy. For a detailed review of the evidence and further discussion, see the ADA??the prevention of diabetes in obese subjects): a landmark study. Poster presented at the International Congress on Obesity (ICO), San Paulo, Brazil, 2002
11. Buchanan TA, Xiang AH, Peters RK, Kjos SL, Marroquin A, Goico J, Ochoa C, Tan S, Berkowitz, Hodis HN, Azen SP: Preservation of pancreatic β-cell function and prevention of type 2 diabetes by pharmacological trewatment of insulin resistance in high-risk hispanic women. Diabetes 51:2796 -2803, 2002
12. Engelgau ME, Narayan KMV, Herman WH: Screening for type 2 diabetes (Technical Review). Diabetes Care 23:1563-1580, 2000 [erratum appears in Diabetes Care 23:1868 -1869, 2000]
13. American Diabetes Association: Type 2 diabetes in children and adolescents (Consensus Statement). Diabetes Care 23:381-389, 2000
14. American Diabetes Association: Gestational diabetes mellitus (Position Statement). Diabetes Care 27 (Suppl. 1):S88 – S90, 2004
15. The Diabetes Control and Complications Trial Research Group: The effect of intensive treatment of diabetes on the development and progression of longterm complications in insulin-dependent diabetes mellitus. N Engl J Med 329: 977-986, 1993
16. The UK Prospective Diabetes Study Group: Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet 352: 837- 853, 1998
17. The UK Prospective Diabetes Study Group: Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34). Lancet 352:854 -865, 1998
