Update on the treatment of diabetic retinopathy.

OBJECTIVES To describe the classification, clinical features, and evaluation of diabetic retinopathy and to review its conventional as well as most updated management. DATA SOURCES Literature search of Medline up to October 2006. STUDY SELECTION Key words for the literature search were 'diabetic', 'retinopathy', 'treatment', 'laser photocoagulation', 'vitrectomy', 'corticosteroid', 'protein kinase C inhibitor', and 'VEGF inhibitor'. DATA EXTRACTION Original articles, review papers, and book chapters were reviewed. DATA SYNTHESIS Diabetic retinopathy remains one of the leading causes of blindness worldwide. The duration of diabetes and severity of hyperglycaemia are the major risk factors. It progresses from non-proliferative diabetic retinopathy to proliferative diabetic retinopathy through various stages, and the accurate diagnosis of its stage is important. Strict metabolic control and tight blood pressure control can significantly reduce the risk of developing retinopathy and its progression, but are difficult to achieve in clinical practice. Laser photocoagulation and vitrectomy are effective in preventing severe visual loss from sight-threatening diabetic retinopathy and its complications, but both modalities have potential side-effects. Results from clinical trials for protein kinase C inhibitors, intravitreal steroid injections, anti-vascular endothelial growth factor agents, angiotensin converting enzyme inhibitors, and growth hormone inhibitors are promising. Evidence from past clinical trials does not support a role for anti-platelet agents, aldose reductase inhibitors, and advanced glycation end-products inhibitors. CONCLUSION Strict metabolic control, tight blood pressure control, laser photocoagulation, and vitrectomy remain the conventional management of diabetic retinopathy. Further clinical trials exploring the role of protein kinase C inhibitors, intravitreal steroid, anti-vascular endothelial growth factor agents, angiotensin converting enzyme inhibitors, growth hormone, and other potential therapies for diabetic retinopathy are actively ongoing. In the near future, results from these clinical trials may lead to the introduction of additional treatments and a corresponding reduction in the frequency of visual loss due to diabetic retinopathy.