Smoking and blindness

In the “web extra” material for this editorial by Simon P Kelly and colleagues, we forgot to make some final small amendments that the authors had told us about (6 March, pp 537-8). In the third sentence of the section headed “sensitivity analysis,” 61 800 should be 53 900 (consistent with elsewhere in the text and web extra material). The last part of the URL for the web reference W7 where it appears after the table (the second time it appears in the web extra material) is wrong; the correct URL is www.statistics.gov.uk/census2001/pop2001/united_kingdom.asp (as it appears in the list of web references).