Study of inherited visual diseases provides a means by which both normal and aberrant visual processes might be understood. In addition to directly elucidating the pathophysiology of the inherited disease under study, these studies can provide insights into the structure-function relationships of the molecular components of the visual system and their normal physiology. This laboratory is using a number of approaches to study inherited visual diseases affecting the visual system. One approach to understanding inherited visual diseases uses principles of positional cloning to identify genes important in human inherited diseases. Human diseases currently undergoing linkage analysis, gene isolation, or characterization of mutations include Usher syndrome, X-linked retinoschesis, corneal dystrophy, glaucoma, and X-linked familial exudative vitreoretinopathy. We are currently recruiting families with autosomal recessive retinitis pigmentosa and Bietti syndrome in preparation for study of this important group of diseases. The effects of specific genetic alterations, including myosin 7A and the Ush2A, gene on the visual process are being studied. Finally, families with multiple individuals affected by glaucoma and elevated intraocular pressure are being recruited to study the genes affecting these complex diseases.