title: Reply.
authors.affiliation: Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. Electronic address: carinaslidsborg@hotmail.com.
authors.forename: Carina
authors.initials: C
authors.lastname: Slidsborg
authors.affiliation: Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark; Research Center for Vitamins and Vaccines (CVIVA), Bandim Health Project, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Aksel
authors.initials: A
authors.lastname: Jensen
authors.affiliation: Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Julie Lyng
authors.initials: JL
authors.lastname: Forman
authors.affiliation: Department of Clinical Microbiology, Hvidovre Hospital, Hvidovre, Denmark.
authors.forename: Steen
authors.initials: S
authors.lastname: Rasmussen
authors.affiliation: Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Regitze
authors.initials: R
authors.lastname: Bangsgaard
authors.affiliation: Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Hans Callø
authors.initials: HC
authors.lastname: Fledelius
authors.affiliation: Department of Neonatology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Gorm
authors.initials: G
authors.lastname: Greisen
authors.affiliation: Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: de la Cour