Visual function and adaptation across the lifespan

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Objectives: Many species rely heavily on vision. In humans large portions of the brain are dedicated to visual function, and visual impairment is one of the most highly feared disabilities. The eyes and visual system do appear to be capable of adaptation to environmental influences, opening the possibility of favorably altering outcomes, thus reducing visual impairment. The long term objective of my research program is to understand the processes by which development and aging affect the visual system and the extent to which these processes can be altered by visual experience or adaptation. One goal is to study the effects of altered visual experience on eye development using animal models of refractive development. A second goal is to investigate visual function change across the age range of the human lifespan. Approach: In animal models, novel lenses will be used to investigate the role of peripheral focus in eye growth control. The Hartmann-Shack technique, retinoscopy and ocular biometry will be used to investigate aberrations, astigmatism and diurnal variations in refraction as possible sources for the directional signal to eye growth in induced refractive error in animal models. Mathematical modeling across age of retrospective cross-sectional and longitudinal vision related human data will be used to study the effects of development and aging of visual functions. I am also proposing the development of a prospective cross-sectional database of individuals across the age range of the human lifespan for the study of visual function. Novelty: The novelty of this proposal lies in the use of a novel lens design to investigate control of eye growth; precise measurement of diurnal variation of higher order aberrations, refraction and intra-ocular pressure; the prospective study of visual function across the entire age range of the human lifespan for a large number of individuals; the availability of a database containing 25 years of detailed longitudinal vision related information. Significance: The prevalence of myopia is increasing and is now estimated to affect 43% of the North American population and up to 90% of Asian populations. In some populations the increase in the prevalence of myopia has occurred within a single generation suggesting that the change has occurred largely as the result of environmental influences. Preventative therapies have been unsuccessful reflecting the fact that the basic mechanisms which underlie refractive development are still unknown. Virtually every metric of visual function has a period of development to a maximum which subsequently declines into old age. Maximizing development and promoting healthy aging are priorities. Given that vision plays such a vital role in our quality of life, increasing our understanding of the rise and fall of visual function is vital for optimizing development and reducing decline, planning programs, and allocating resources.