Physically essential to sight, a transparent tissue that bends light passing through the eye. To focus light, the lens can change shape by bending. Also, a transparent piece of glass or another material, which is shaped to focus the passage of light through it and into or onto another surface in some other optical device, such as a camera, camera lucida, camera obscura, magnifying glass, telescope, microscope, mirror, projector, etc.Examples: Michelangelo (born Michelangiolo Buonarroti) (Italian, 1475-1564), the left eye of David, 1501-04, marble, entire statue 17 feet high, Galleria dell'Accademia, Florence. The pupil was carved not to represent its form, but to represent its values. The sculptor has retained a bit of marble inside the pupil in order to create a highlight. A see thumbnail to rightdetail of David's head. See colossal, detail, Renaissance, and sculpture.Also see blow-up, close-up, enlargement, field and field of view, filter, fish-eye lens, kaleidoscope, ophthalmology, refraction, sclera, telephoto, and wide-angle lens.