PURPOSE: Demonstrate the optics of the eye and corrections of optical defects.

DESCRIPTION: The eye model is an oval tank, filled with water representing the aqueous humor, with a lens representing the eye lens on one end and a screen representing the retina with three positions: normal, nearsighted, and farsighted.

The eye lens focuses light from a distant object onto the retina, which is positioned in the center of three retinal locations. The image on the retina can be seen to be inverted by the eye lens. If the retina is moved to the far position, the eye is too long, producing nearsighted vision. This can be corrected using a diverging lens as the eyeglass. If the retina is moved to the near position, the eye is too short, producing farsighted vision. This can be corrected by using a converging lens eyeglass. Instruction sheet, including list of corrective lenses and positions for various optical elements is with the eye model.

Television can be used to make the action visible to a large group.



EQUIPMENT: Eye model filled with water, set of lenses, light source with object cross, and instructions, with TV system.

SETUP TIME: 5 min..

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