Presbyopia: an animal model and experimental approaches for the study of the mechanism of accommodation and ocular ageing.

During the last hundred years, observations on normal and a few aniridic human eyes, together with population studies on the age-dependent decline in accommodative amplitude, resulted in the formulation of theories of human accommodation, and led to the concept that presbyopia is an inevitable consequence of ageing. However, such studies failed to substantiate these theories and concepts or to reveal the fundamental mechanisms of accommodation and its age-dependent loss. Detailed understanding of these mechanisms and the environmental, dietary, and behavioural factors that may influence the development of presbyopia will require controlled studies and, in some cases, invasive experimental manipulations that can only be achieved through the use of an animal model. This paper reviews some of the evidence indicating that the rhesus monkey is a highly suitable primary animal model for such studies, as well as for studies on other aspects of ocular ageing, and reviews some of the techniques and experimental approaches that have already been adapted or developed for such studies.