Gene characterization holds great promise for understanding molecular mechanisms of disease. Although glaucoma gene identification is very valuable and allows assessment of an individual's genetic risk, it is not by itself sufficient to answer detailed questions about pathogenesis. Despite the recent identification of a number of glaucoma genes, there are still many questions regarding the ways in which mutations in these genes cause disease. The mouse system, including the ability to alter specific genes, provides a powerful experimental system for hypothesis testing and molecular dissection of pathogenesis subsequent to gene identification. The ability to control both genetic and environmental factors will allow the use of mice to identify modifier genes that alter complex glaucoma phenotypes and that are especially difficult to identify in human families. By providing a bridge between gene identification and tests of gene function, mouse studies will be an important complement to those in humans and other species. This article summarizes the recent use of mice and the future potential of applying approaches of mouse genetics to intraocular pressure and glaucoma research.