Diabetic retinopathy is a common and specific microvascular complication of diabetes, and remains the leading cause of preventable blindness in working-aged people. It is identified in a third of people with diabetes and associated with increased risk of life-threatening systemic vascular complications, including stroke, coronary heart disease, and heart failure. Optimum control of blood glucose, blood pressure, and possibly blood lipids remains the foundation for reduction of risk of retinopathy development and progression. Timely laser therapy is effective for preservation of sight in proliferative retinopathy and macular oedema, but its ability to reverse visual loss is poor. Vitrectomy surgery might occasionally be needed for advanced retinopathy. New therapies, such as intraocular injection of steroids and antivascular endothelial growth-factor agents, are less destructive to the retina than are older therapies, and could be useful in patients who respond poorly to conventional therapy. The outlook for future treatment modalities, such as inhibition of other angiogenic factors, regenerative therapy, and topical therapy, is promising.

Objective-To summarize the prevalence of retinal vein occlusion (RVO) from studies in the United States, Europe, Asia, and Australia. Design-Pooled analysis using individual population-based data.Participants-Individual participant data from population-based studies around the world that had ascertained RVO from fundus photographs.Methods-Each study provided data on branch RVO and central RVO by age, sex, and ethnicity. Prevalence rates were directly age and sex standardized to the 2008 world population aged 30 years and older. Estimates were calculated by study and, after pooling, by ethnicity. Summary estimates included studies in which RVO was assessed from fundus photographs on ≥2 fields of both eyes. Main Outcome Measures-Any RVO, CRVO, or BRVO.Results-The combined pooled data contained 68,751 individuals from 15 studies, with participants' ages ranging from 30 to 101 years. In analyses of 11 studies that assessed ≥2 fundus fields of both eyes (n=49,869), the age-and sex-standardized prevalence was 5.20 per 1000 (confidence interval [CI], 4.40-5.99) for any RVO, 4.42 per 1000 (CI, 3.65-5.19) for BRVO, and 0.80 per 1000 (CI, 0.61-0.99) for CRVO. Prevalence varied by race/ethnicity and increased with age, but did not differ by gender. The age-and sex-standardized prevalence of any RVO was 3.7 per 1000 (CI, 2.8-4.6) in whites (5 studies), 3.9 per 1000 (CI, 1.8-6.0) in blacks (1 study), 5.7 per 1000 (CI, 4.5-6.8) in Asians (6 studies), and 6.9 per 1000 (CI,3) in Hispanics (3 studies). Prevalence for CRVO was lower than BRVO in all ethnic populations. On the basis of these data, an estimated (CI, adults are affected by RVO, with 2.5 million (CI, 1.9-3.1) affected by CRVO and 13.9 million (CI, 11.5-16.4) affected by BRVO. Study limitations include non-uniform sampling frames in identifying study participants and in acquisition and grading of RVO data.Conclusions-Our study provides summary data on the prevalence of RVO and suggests that approximately 16 million people may have this condition. Research on preventive and treatment strategies for this sight-threatening eye disease is needed.Retinal vein occlusion (RVO) is one of the most common causes of acquired retinal vascular abnormality in adults and a frequent cause of visual loss. Despite being recognized at least as early as 1855 1 and the subject of more than 3000 publications, there are few data on the prevalence of RVO in the general population, with current estimates derived largely from studies in white populations. [2][3][4] More recently, population data have emerged from other racial/ ethnic groups, such as in Chinese, 5 Hispanics, 6 and Asian Malays. 7 The reported prevalence of RVO varies between 0.3% 4 and 1.6%. 3 The variability in prevalence rates is likely related to the small number of RVO cases in any single study, differing study methodologies (e.g., retinal photography), and possible racial/ethnic differences in distributions of RVO risk factors.Because of these limitations, estimates of RVO prevalence have been imprecise. Furthermo...