Over the past decade, substantial promise for a future understanding of glaucoma has been seen due to the dramatic progress in medical and molecular genetics.While the research on glaucoma genetics was entirely descriptive for more than a century, recent advances in molecular genetics have transformed this field completely. In recent years, a considerable number of specific mutations have been identified in the genetic code of patients that segregate with specific glaucomatous disease phenotypes. As the human genome has been sequenced and the methods that are used to identify disease-related genes are rapidly improving, more genes that are causatively involved in the pathogenesis of glaucoma will be discovered. This will finally lead to a new and better concept to classify different forms of glaucoma, but will also enable scientists and clinicians to better understand the pathogenesis of glaucoma at the level of cell and molecular biology. For many of those genes that have already been identified, transgenic animal models were developed, which have considerably improved our understanding of the biological function of glaucoma-related genes and their gene products. The development animal models based on the molecular changes in the genome of glaucoma patients will continue and provide controlled biological systems to study the biological role of the respective genes and their interaction with genetic and environmental factors.