Age-related ocular surface failure: A narrative review.

Ageing has been defined as a specific individual plasticity and remodeling capacity to the environment' insults and stimuli. The precise physiology of aging is not entirely understood. Several theories have been proposed and included programmed cell death, genetic mutations, the epigenetic clock, wear-and-tear and free radicals. Ocular surface represents a complex morpho-functional unit composed of different tissues that strictly interact to preserve homeostasis and function. Ageing severely disrupts this system by means of inflammaging and immunosenescence, leading to ocular surface failure in older population.