| Variable | Visual acuity ≥0.55
          Odds ratio (95% CI) p-value | Visual acuity ≤0.05
          Odds ratio (95% CI) p-value | 
      
        | Year of operation (2002-2010) | 1.20 (1.17-1.23) | <0.0001 | 0.96 (0.94-0.99) | 0.002 | 
      
        | Sex (female versus male) | 0.94 (0.82-1.07) | 0.32 | 0.86 (0.76-0.97) | 0.017 | 
      
        | Eye disease (No versus Yes) | 1.73 (1.53-1.97) | <0.0001 | 0.67 (0.60-0.76) | <0.0001 | 
      
        | General disease (No versus Yes) | 0.67 (0.59-0.76) | <0.0001 | 1.12 (0.99-1.28) | 0.077 | 
      
        | Age (≥80 years) ≤59 60-69 70-79 | 1 2.01 (1.60-2.51) 2.15 (1.77-2.60) 1.99 (1.67-2.38) | 0.022 <0.0001 0.002 | 1 0.94 (0.79-1.11) 0.65 (0.56-0.76) 1.73 (1.45-2.07) | 0.176 <0.0001 <0.0001 |