Visual acuity (VA) impairment and cardiovascular disease (CVD) are major global health burdens. Although impaired VA is linked to elevated all-cause mortality risk, its association with CVD mortality, particularly in older population, remains inadequately explored and inconsistent. This study aimed to quantify the burden of VA impairment and investigate its association with CVD mortality in a large cohort of Chinese older adults. This multicenter cohort study used data from the Basic Public Health Services in China. A total of 2,517,662 participants 65 years of age or older from 4 cities (Zaozhuang, Luzhou, Zunyi, and Shenzhen) were included between 2017 and 2023. Presenting visual acuity of the better-seeing eye (BVA) was measured using a standard logarithmic tumbling E chart. Mortality data were ascertained via linkage to the China Population Death Information Registration System, with follow-up through December 31, 2024. Cox proportional hazards models were used to estimate HRs and 95% CIs for the association between VA and mortality, with adjustments for demographic, lifestyle, clinical and geographic factors. Stratified analysis, competing risk analysis, dose-response analysis, and extensive sensitivity analyses were performed to further investigate the relationship. Among the 2.52 million participants (mean age: 70.67 years), 42.5% had VA impairment. Over a mean follow-up of 4.99 years (accumulating 12,560,718.9 person-years), 348,501 deaths occurred, including 153,758 CVD deaths. In the fully adjusted model, each 1-logMAR unit increase in BVA (greater visual impairment) was associated with a 3% higher risk of all-cause mortality (HR: 1.03; 95% CI: 1.03-1.04) and a 3% higher risk of CVD mortality (HR: 1.03; 95% CI: 1.02-1.03). A graded association was observed when VA was categorized by quartiles, with the worst quartile (Q4) showing significantly elevated risks for all-cause (HR: 1.25; 95% CI: 1.24-1.26) and CVD mortality (HR: 1.30; 95% CI: 1.28-1.32) compared to the best quartile (Q1). Stratified analysis indicated that the association was stronger in younger participants (65-70 years). Dose-response analysis revealed a significant nonlinear association, with mortality risk rising steeply at lower levels of impairment and plateauing at higher levels. Competing risk and sensitivity analysis confirmed the robustness of these findings. Beyond its traditional ocular role, VA impairment emerges as a sentinel marker of cardiovascular vulnerability and a functional barometer of biological aging. Situating cardiovascular risk within the broader landscape of functional aging and prioritizing holistic functional preservation could be pivotal for promoting longevity and achieving healthy aging goals.