?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aulast=Cumberland&rft.au=Cumberland%2C+PM&rft.aufirst=PM&rft.pages=841+-+843&rft.date=June+2014&rft.issue=6&rft.title=British+Journal+of+Ophthalmology&rft.volume=98&rft.atitle=Ophthalmic+statistics+note%3A+The+perils+of+dichotomising+continuous+variables&rft.issn=0007-1161&rft.genre=article