MLN4924 hypertension is considered to cause elevation of inflammatory cytokines such as tumor necrosis factor-alpha, interleukin-6. Besides, an elevation of C-reactive protein level has been detected when individual blood pressure raises. Considering that cataract is closely related to intense systemic inflammation, hypertension is therefore involved in the pathological pathway of cataract development through an inflammatory mechanism. Beyond that, Lee et al. reported that hypertension could induce conformation structure alteration of proteins in lens capsules, thereby exacerbating the cataract formation. Although several plausible mechanisms have been proposed based on laboratory results, the conclusions from epidemiologic studies remain inconsistent. It is important to determine the effects of hypertension on cataract risk, due to increasing hypertension morbidity. Given the fact that individual studies may be limited because of sample size, therefore, a metaanalysis was conducted to quantitatively confirm the relationship between hypertension and cataract risk. What’s more, many scholars hold the opinion that hypertension might be linked to cataract by other main components of MS, a subgroup analysis containing studies adjusted for these confounders will be helpful to figure out the truth. The results of the present meta-analysis containing cohort and case-control or cross-sectional studies showed that hypertension was associated with an increased risk of cataract without regard for cataract types. It was true among both Mongolians and Caucasians. Besides, this association was demonstrated to be independent of the effect of pathoglycemia, obesity and dyslipidemia. An increased incidence of PSC related to hypertension was also revealed in both cohort and case-control or cross-sectional studies. There was no evidence of a significant relationship between hypertension and nuclear cataract. In terms of cortical cataract, the results from cohort studies conflicted with those from case-control and cross-sectional studies. But one must treat the pooled results in the subgroup analyses with caution due to the limited number of involved studies. According to results reported by Sabanayagam et al., people with severe hypertension have a higher risk of cataract than those with mild hypertension. Several studies indicated a linear positive correlation between blood pressure and cataract risk, which is in accord with our results. Duration of hypertension is also an important factor, indicating a relationship between longer duration and increased cataract risk. Many studies suggested that hypertension is linked to cataract development in part because of anti-hypertension medications. Cumming et al. reported a significant association between cataract risk and potassium-sparing diuretics, which is biologically plausible, as this kind of anti-hypertension medications can disturb the electrolyte balance across the lens fiber membrane. Several other studies indicated that exposure to beta-blockers can also promote cataract formation ; which is supported by experimental studies demonstrating that the use of beta-blockers could elevate levels of intracellular cyclic adenosine monophosphate.