Cases of word usage

1) a person suffering from faulty vision caused by the lens of the eye having the wrong shape (astigmatic)

2) a meeting-point of rays of light, heat etc; a point, distance, where the sharpest outline is given (to the eye, through a telescope, through a lens on a camera etc) (focus)

3) to make (a person or thing) appear larger (as with a lens or microscope); to exaggerate (something) (magnify)

4) a framed lens for one eye (monocle)

5) a movable cover for a window, used to keep out light; the device that opens to admit light through the lens of a camera (shutter)