Visual impairment and ten-year mortality: the Liwan Eye Study

Abstract

Objectives: To explore associations between visual impairment (VI) and mortality in an adult population in urban China.

Methods: The Liwan Eye Study was a population-based prevalence survey conducted in Guangzhou, Southern China. The baseline examination was carried out in 2003. All baseline participants were invited for the 10-year follow-up visit. VI was defined as the visual acuity of 20/40 or worse in the better-seeing eye with habitual correction if worn. Correctable VI was defined as the VI correctable to 20/40 or better by subjective refraction, and non-correctable VI was defined as the VI correctable to worse than 20/40. Mortality rates were compared using the log-rank test and Cox proportional hazards regression models.

Results: Of the 1399 participants (mean age: 65.3 ± 9.93 years; 56.4% female) with available baseline visual acuity measurement, 320 participants (22.9%) had VI. After 10 years, 314 (22.4%) participants died. Visually impaired participants had a significantly increased 10-year mortality compared with those without VI (40.0% vs. 17.2%, P < 0.05). After adjusting for age, gender, income, educational attainment, BMI, history of diabetes and hypertension, both VI (HR, 1.55; 95% CI, 1.14-2.11) and non-correctable VI (HR, 2.72; 95% CI, 1.86-3.98) were significantly associated with poorer survival, while correctable VI (HR, 0.99; 95% CI, 0.66-1.49) was not an independent risk factor for 10-year mortality.

Conclusions: Our findings that VI, particularly non-correctable VI, predicting poorer survival may imply the underlying mechanism behind VI-mortality association and reinforce the importance of preventing and treating disabling ocular diseases to prevent premature mortality in the elderly.

Fig. 1. Surval curves for visual impairment and 10-year mortality.

Survival curves were adjusted for age, sex, history of diabetes and hypertension, body mass index, educational attainment and family income. Blue, red and green curves indicate the surivial curve for no visual impairment, correctable and non-correctable visual impairment, respectively.