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(Course Logo: Adult walking with cane and holding a child's hand)Designing for the Life Span Segment 3

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Slide 13[D]

Slide 13 Content

Vision and Aging: The human eye is a "camera" device - meaning that it uses a lens to focus light on a surface called the retina. This eye is edge sensitive - meaning that people see things as figures against backgrounds. Motion is detected at the periphery of vision. The eye sees a range of colors with varying degrees of clarity. The eye has limitations in acuity, pattern recognition and motion detection.

Narration of Slide 13

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"Cameras" are modeled after the human eye. As we discuss imaging further, objects will be referred to as "figures" and the environment in which an object is located will be referred to as a "ground." Designers frequently discuss the relationship between shapes and backgrounds as a "figure/ground" relationship.

The human eye perceives figures in terms of edges... the eye is edge sensitive. Light passes through the cornea and is focused by the lens through the ability of the muscle controllers to change the shape of the lens - either compressing it or extending it. Figure/ground images in light are focused on the retina of the eye. The clearest focus is obtained when the light from figures is concentrated near the fovea at the rear of the eye.

Light must pass through a fluid in the eye that maintains overall eye shape called the vitreous humor. This fluid may change in both color and consistency over time.

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