illusion.

A false interpretation of a real sensation. Example: when one is on a motionless train next to another train just starting off, the sense that one is moving backward and the other train is standing still.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

iris.

The colored, circular disc of the eye, suspended behing the transparent part of the eye, the cornea. Its hind surface rests on the lens of the eye. . . . The iris . . . contains . . . muscles [that] control the size of the pupil.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

jaundice.

Yellowness of the skin, lining tissues, and secretions due to bile pigments in the blood.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

lens.

1. A crystal or piece of glass that bends rays of light passing through it. . . . 2. The transparent egg-shaped body lying behind the pupil of the eye, called the crystalline lens of the eye.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

lenticular.

1. Resembling or relating to a lens. 2. Relating to the crystalline lens of the eye.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

livid.

A pale, leaden, bluish color. The discoloration produced by an injury.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

macula.

A pigmented spot upon the skin. 2. A spot in the retina. . . .

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

melanin.

Black or dark-brown pigment found, in some degree, in all people and responsible for complexion.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

monocular.

1. Relating to , or affecting, one eye. 2. Having a single eyepiece as in the monocular microscope.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.

myopia.

Nearsightedness, due to a greater than normal length of the eyeball from front to back, resulting in the image falling in front of the retina. Lenses . . . that push the image back onto the retina are used to correct this condition.

—Layman’s Medical Dictionary, Harry Swartz, M.D., 1963.