[1] Univ Med Gottingen, Klin Augenheilkunde, Robert Koch Str 40, D-37075 Gottingen, Germany
[2] Univ Klinikum Freiburg, Augenklin, Freiburg, Germany
[3] St Franziskus Hosp Munster, Augenabt, Retinol, Munster, Germany
[4] Univ Klinikum Koln, Augenklin, Cologne, Germany