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.
Carcinoma in situ (CIS), also known as in situ neoplasm, is a group of abnormal cells. Dysplasia is the earliest form of pre-cancerous lesion recognizable in a biopsy. 2  Dysplasia can be low grade or high grade. 3  High grade dysplasia may also be referred to as carcinoma in situ.