1. Department of Ophthalmology, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
2. Department of Biology, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
3. Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1627, 70211 Kuopio, Finland