InvestigativeOphthalmology & Visual Science (IOVS),published online several times a month, is an official journal of theAssociation for Research in Vision and Ophthalmology (ARVO), an internationalorganization whose purposes are to encourage and assist research, training,publication, and dissemination of knowledge in vision and ophthalmology.Included are original contributions that emphasize clinical and laboratoryhypothesis-based research with statistically good results that clearly advancethe fields of ophthalmic and vision research. IOVS de-emphasizes purely descriptive research.