[1] Univ Oulu, Dept Ophthalmol, Res Unit Clin Med, Oulu, Finland
[2] Univ Oulu, Med Res Ctr, Oulu, Finland
[3] Oulu Univ Hosp, Oulu, Finland
[4] Oulu Univ Hosp, Res Serv Unit, Oulu, Finland
[5] Univ Oulu, Oulu Univ Hosp, Res Unit Surg Anesthes & Intens Care, Oulu, Finland
[6] Univ Oulu, Oulu Univ Hosp, Dept Ophthalmol, POB 21, Oulu 90029, Oys, Finland
[7] MRC Oulu, POB 21, Oulu 90029, Oys, Finland