1. From the Centre for Ophthalmology, Institute for Ophthalmic Research, and the
2. Department of Medical Biometry, University of Tu¨bingen, Tu¨bingen, Germany; and the
3. From the Centre for Ophthalmology, Institute for Ophthalmic Research, and the3Division of Motility Disorders, Periocular Surgery and Pediatric Ophthalmology, Centre for Ophthalmology, Tu¨bingen, Germany.