Chapter 3 - Macaque Models of Visual Development and Disability

Abstract

The Old World macaque monkey has been shown to provide an excellent model for normal visual development in humans and for understanding clinically important developmental disorders of vision. Animal studies in general have contributed greatly to our understanding of the vulnerability of the visual system to early abnormal visual experience. These studies of basic visual development provide reasonable support for the weeks-equals-months relationship for spatial vision. The most common cause of vision loss in children is amblyopia. Amblyopia is classically defined as a loss of visual acuity in one eye with no obvious accompanying pathology. The normal development of visual function proceeds in a systematic way in both human and nonhuman primates. Behavioral studies of macaque monkeys raised under visual conditions that mimic human developmental visual disorders were conducted to determine how well the monkey model reflected the visual losses found in human amblyopia and to explore the underlying neural mechanisms. These studies showed direct causality between visual impediment and the development of amblyopia and provided definitive information on the nature of the critical period for vision. They also provided insight into the neural basis of amblyopia and had a direct impact on the way in which amblyopia is treated in children.