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. 2026 Oct 1;13:1969759. doi: 10.3389/fmed.2026.1969759

Figure 2.

Forest plots showing random-effects meta-analyses of continuous associations between exposure to PM2.5, black carbon, and NO2 and cataract-related outcomes. Individual study hazard ratios with 95% confidence intervals are shown as squares and horizontal lines, with square size reflecting study weight; diamonds represent pooled estimates. The pooled estimates are HR 1.036 for PM2.5, 1.010 for black carbon, and 1.041 for NO2. Between-study heterogeneity is very high for PM2.5, high for NO2, and lower for black carbon. Study weights and heterogeneity statistics are displayed for each analysis.

Random-effects meta-analyses of continuous associations between ambient air-pollutant exposure and cataract outcomes. PM₂.₅: HR per 1 µg/m3 increase, NO₂: HR per 10 µg/m3 increase, Black carbon: HR per study-specific IQR increase. An HR >1 indicates a higher rate of the cataract-related outcome with greater pollutant exposure, whereas an HR <1 indicates a lower rate.