Fig. 5.5 Incidence of CRVO by age in the Beaver Dam Eye Study. BDES Beaver Dam Eye Study (Data from Klein

et al.29)

Five– Year Incidence (%)

Five– Year incidence of CRVO versus age

0.6

Age

5.4.1.4 Hemicentral Retinal Vein Occlusion

In a retrospective case series of 28 HCRVOs, the mean age of onset was 63 (range 35–82).2 In a case series of 130 patients with HCRVO, 12% of patients were less than 45, 30% were 45–64, and 58% were greater than or equal to 65.20 The median age was 68.1 with range 14–98.20 In the EDCCS, 79 patients with HCRVO were studied. The median age was in the decade 65–74 years with 95% of patients older than 45.47

5.4.2 Gender

5.4.2.1 Pooled Retinal Vein Occlusion

Although many case series report higher proportions of males than females, there is a problem of referral or recruiting bias.11,20,43 Prospective, pop- ulation-based studies are inconsistent but do not suggest a strong association with gender.59 In the BDES, among a population of age 43–86, the prevalence of pooled RVO was the same in men and women (0.8%).8 In the BMES, among a population 49 or older, the prevalence of RVO was similar in men and women (1.4% and 1.8%, respectively).8,39 On the other hand, in the Beijing Eye Study, 56.8% of pooled RVOs occurred in

women and 43.1% in men.37 In a meta-analysis of 15 studies of 68,700 subjects worldwide, the standardized prevalence of pooled RVO did not vary by gender.44 The standardized prevalences for men and women were 3.74 per 1,000 adults (95% CI 3.17–4.31) and 5.04 per 1,000 adults (95% CI 3.75–6.32), respectively.44

In the BMES, gender was not a risk factor for prevalence or incidence of pooled RVO.9,39 Similarly, in the BDES, gender was not a risk factor for prevalence or 5-year incidence of CRVO or BRVO.29

5.4.2.2 Branch Retinal Vein Occlusion

Some case series of BRVOs have higher proportions of males and others higher proportions of females.17 Collecting 1,166 cases from five retrospective studies of BRVO, the weighted percent- ageofmaleswas48.3%.2,13,20,25,55Population-based studies do not suggest an association with gender. In a meta-analysis of 15 population-based studies, the standardized prevalence (/1,000) of pooled RVO did not vary by gender.44 The standardized prevalences for men and women were 3.74 per 1,000 adults (95% CI 3.17–4.31) and 5.04 per 1,000 adults (95% CI 3.75–6.32), respectively.44 In the BDES, gender was not a risk factor for prevalence of BRVO.29 In the EDCCS, gender was not associated with BRVO.51