Tear film deficiencies pharmacology of eye drops and toxicity.

Our knowledge of the diagnosis and treatment of multifactorially induced dry eye has increased dramatically during the past few years. Major progress has taken place in the development of objective methods of evaluating and differentiating disturbances of the ocular lubrication. Various in vivo techniques for the diagnosis of tear film and corneal pathologies, including fluorophotometric tear flow, scanning confocal microscopy, infrared thermography, and fluorogenic substrate techniques, can be used quantitatively and qualitatively in clinical research. Eyedrop side effects such as epithelial cell toxicity and, especially, changes in epithelial membrane permeability after the administration of locally applied ophthalmic preparations are now detectable under in vivo conditions.