Members of the DEWS Definition and Classification. Subcommittee developed a contemporary definition of dry eye disease and a three-. part classification system based on etiology, causative mechanisms and disease. severity.
Metaplasia. Definition: Metaplasia is the reversible replacement of one differentiated cell type with another differentiated cell type. Metaplasia causes precursor cells to change their cell fate, and do not change existing differentiated cells.he most common epithelial metaplasia is columnar to squamous (squamous metaplasia), as occurs in the respiratory tract in response to chronic irritation.
Metaplasia is a reversible reprogramming of stem cells of the epithelium. Usually, squamous metaplasia is observed in the endocervix. However, less frequently, tubal metaplasia may develop, replacing nonciliated columnar cells by ciliated columnar cells, similar to fallopian tube epithelium.