作者单位:Univ Penn, Scheie Eye Inst, Ctr Prevent Ophthalmol & Biostat, Philadelphia, PA 19104 USA[1]Calif Pacific Med Ctr, Dept Ophthalmol, San Francisco, CA USA[2]Univ Calif San Francisco, Francis I Proctor Fdn, Sch Med, San Francisco, CA 94143 USA[3]Univ Tubingen, Ctr Ophthalmol, Tubingen, Germany[4]