Global Associations of Ambient Air Pollution and Glaucoma: A Systematic Review and Meta-Analysis

Abstract

Purpose : The hazardous effects of air pollution on the lungs and heart are well established. The effects on the eye, which is directly exposed to air pollution, are less known. The purpose of our study was to synthesize the existing evidence on the global associations of ambient air pollutants with glaucoma.

Methods : This work was conducted in accordance with the standards and guidelines of Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA). MEDLINE, EMBASE, and Scopus were searched for articles until September 30, 2021. Inclusion criteria included studies of adults, aged 40+ years, that provided measures of association between nitrogen dioxide (NO₂), carbon monoxide (CO), sulfur dioxide (SO₂), ozone (O₃), particulate matter (PM) less than 2.5µm in diameter (PM_2.5), and PM less than 10µm in diameter (PM₁₀) and glaucoma. Articles were screened, extracted, and graded for certainty of the evidence by two independent reviewers. Pooled odds ratio (OR) estimates and 95% confidence intervals (CI) were calculated using a random-effects meta-analysis model in which study weights were inversely related to the total variance and between-study variability was estimated using restricted maximum likelihood. PROSPERO registration ID: CRD42021250078.

Results : A total of 403 articles were identified. Of these, 4 studies including 181,801 people met the criteria for inclusion in our systematic review and meta-analysis. Consistent evidence for an association was found between PM_2.5 and glaucoma with 4 out of 4 studies reporting a positive association. The pooled OR for each 10 µm/m³ increase of PM_2.5 on glaucoma was 1.18 (95% CI: 0.95-1.47). Inconsistent evidence was found for the associations between the other pollutants and glaucoma.

Conclusions : Current evidence suggests there may be an association between PM_2.5 and glaucoma. Strengths of the current study included the use of recent evidence in which large sample sizes were utilized while limitations included low response rates, the use of self-reported glaucoma measures, and cross-sectional study designs. More studies, especially those using longitudinal data, are needed and potential mechanisms should be explored by investigating interactions with genetic factors or inflammatory markers that may be involved in the causal pathway.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.