The ocular lens: a classic model for development, physiology and disease.

Millions are rendered blind or exhibit visual impairment due to pathologies of the lens of the eye. Lens research therefore addresses the direct need to gain insights into the cellular and molecular basis of disease, but, moreover, serves as a valuable experimental system to answer fundamental biological questions. This themed issue showcases the scientific knowledge of the processes involved in the development, structure, ultrastructure, physiology and pathology of the lens and how this information has the potential to significantly further knowledge in various fields of research. The issue is divided into three main areas. Firstly, the lens is discussed as a developmental model for embryonic induction, as an elegant system for studying the role of growth factors in development, and for analysis of the molecular control and cellular basis of cellular differentiation. The genetic basis of disorders of lens development, including paediatric cataract (lens opacity), are also discussed in this section. Secondly, adult lens structure and ultrastructure are covered, as well as the lens as a model for homeostasis and solute exchange. Finally, the papers in the latter part of the special issue review lens pathology, including the lens as a model for normal and pathological ageing, vitreoretinal influences on lens function and cataract and the lens as a model for fibrotic disease. Overall, the articles highlight the lens as a continuing, very important and attractive model system for biologists working in many different research areas.