The dry eye is a complex multifactor illness of the tear film and of the ocular surface characterized by symptoms of discomfort, vision alterations, and instability of the pre-corneal tear film which may bring about potential damage on the ocular surface. Instability of the film will produce increasing osmolarity of the tear film which will trigger epithelium osmotic lesions and inflammation. As these changes take place on the ocular surface, neurophysiologic mechanisms of homeostasis will be altered which will complicate the process even further with the cropping of vicious physiopathologic circuits.
Part of the book: Ocular Surface Diseases