Association of residential air pollution with visual impairment in adults: The UK Biobank study.

Purpose: To investigate the association of joint exposure to residential air pollutants with different severities of visual impairment (VI) in adults.

Methods: Exposure to particulate matter and oxides of nitrogen were evaluated in 95,246 adults aged 40-70 years. Joint exposure to the pollutants was calculated using principal component analysis to create an air pollution score. Subjects were categorized by distance visual acuity into bilateral normal vision, near normal vision, unilateral VI, socially significant VI, and blindness and low vision.

Results: A unit rise in air pollution score was associated with 9.2 %, 4.1 %, and 1.8 % increased risks of blindness and low vision, adjusted OR (AOR) = 1.092 (95 % CI, 1.057-1.129); socially significant VI, AOR = 1.041 (95 % CI, 1.016-1.066); and unilateral VI, AOR = 1.018 (95 % CI, 1.007-1.029), respectively. Compared to subjects in the lowest quartile of air pollution score, those in the highest quartile had 69.2 %, 30.5 %, and 9.9 % greater risks of blindness and low vision, AOR = 1.692 (95 % CI, 1.355-2.114), socially significant VI, AOR = 1.305 (95 % CI, 1.127-1.513), and unilateral VI, AOR = 1.099 (95 % CI, 1.035-1.167), respectively while those in the third quartile had 40.5 % and 25.6 % higher risks of blindness and low vision, AOR = 1.405 (95 % CI, 1.121-1.760) and socially significant VI, AOR = 1.256 (95 % CI, 1.086-1.453), respectively. There was a significant trend of increasing risk of blindness and low vision, as well as socially significant VI, as pollution levels rose.

Conclusion: Joint exposure to air pollutants increased the risks of poor vision and blindness, suggesting that reducing such exposure could alleviate the disease burden of VI.