Animal models of dry eye.

BACKGROUND: The causes of dry eye include lacrimal gland insufficiency, meibomian gland dysfunction, impairment of the neuronal innervation and environmental stress - all leading to irritation of the ocular surface. Several animal models have been developed to imitate different pathophysiologic mechanisms in the development of dry eye. Understanding the characteristics and limitations of these models will help researchers choose the right models to address specific problems and develop new treatment modalities in dry eye.
METHODS: Medline searches were performed to identify English language articles relating to different animal models of dry eye. Manual cross-referencing was also performed and some historical articles were included. RESULTS AND
CONCLUSION: A huge variety of animal models exists, mimicking different pathophysiologic mechanisms which can cause dry eye. The mouse is the model most commonly used to study autoimmune mechanisms, because of the diversity of different knockout and transgenic strains and good availability of antibodies. For studying dry eye signs, rabbit or dog models are more suitable, because they present decreased tear secretion and ocular surface changes, have longer lifespans, and offer better accessibility of the ocular surface. For studying special causes of dry eye, such as defects of neuronal reflex loops, environmental changes, or evaporative dry eye, the model of choice should recapitulate the underlying pathophysiologic mechanism.