Decreased Unilateral Acuity Associated with Increased Cardiovascular-related Mortality

Study shows that the classification of visual impairment based on the visual acuity of the better eye not only overlooked the adverse effects of mildly reduced visual acuity, particularly in cases of unilateral visual acuity decline, but also underestimated the impact of such impairment. Photo: Fu C,et al. Transl Vis Sci Technol. July 23, 2025. Click image to enlarge.  Visual impairment is known to be associated with increased risk of cognitive impairment, dementia, depression, psychosis and Parkinson’s disease, but most studies have focused primarily on individuals with severely impaired acuity. In a recent study, researchers investigated the association between the full spectrum of visual acuity categories and mortality due to cardiovascular disease (CVD), cancer or “all-cause” mortality, using data from the prospective UK Biobank study. The findings were reported in Translational Vision Science & Technology.A total of 131,468 participants between the ages of 40 and 79 with visual acuity measurement were included. Visual acuities of both eyes were used to assign each participant into one of the following groups: bilateral normal, unilateral near normal, bilateral near normal, unilateral visual impairment, mild visual impairment, and low vision.Over a median follow-up of 13.5 years, a total of 9,372 deaths were recorded, including 49.9% from cancer and 20.5% from cardiovascular disease. Compared with the bilateral normal vision group, participants with decreased visual acuity had increased risks of all-cause and CVD-related mortality with dose-response curves, but no elevated risk of cancer-related mortality was observed. Decreased unilateral visual acuity but not bilateral near normal vision was associated with increased risks for all-cause and CVD-related mortality.Participants under 60 years with unilateral visual impairment had increased risks of both all-cause and CVD-related mortality, whereas those with bilateral near-normal vision had an increased risk of CVD-related mortality.Those with decreased unilateral visual acuity (unilateral near normal and unilateral visual impairment) and WHO-defined visual impairment (whether mild or low vision) faced increased risks of all-cause and CVD-related mortality. The association between visual impairment and mortality risk was supported in other studies, with chronic stress being a potential contributing factor.A previous study suggested that increased allostatic load (the cumulative burden of stress) served as a mediator between visual impairment and elevated levels of all-cause and CVD-related mortality risks. Allostatic load is associated with an increased risk for CVD incidence, the researchers explained in their article, and with low socioeconomic status and a lack of social support.Other studies using similar visual acuity categories also showed that decreased unilateral visual acuity was associated with lower socioeconomic status, lack of support and poorer general health. These individuals may experience more significant chronic stress and reduce their accessibility to healthcare because of these challenges, further contributing to the elevated mortality risk.“Unlike those with decreased unilateral visual acuity, individuals in the bilateral near-normal vision group did not exhibit lower socioeconomic status or limited support compared with those with bilateral normal vision,” the authors wrote in their article. “This may partly explain the comparable risks of all-cause and CVD-related mortality observed between the two groups.”These findings highlighted the importance of adopting a broader concept of visual acuity classification method beyond “visual impairment” in eye care and visual sciences, the researchers argue. “Integrating strategies to achieve bilateral vision balance in clinical practice may enable ophthalmologists and optometrists to help reduce the mortality risk of individuals with decreased unilateral visual acuity,” the authors concluded in their paper. Click here for the journal source. Fu C, Chen J, Gu Q, et al. Unilateral visual impairment and increased mortality: the UK Biobank Cohort Study. Transl Vis Sci Technol. July 23, 2025. [Epub ahead of print.]This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.