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.

nictitation.

Excessive winking.

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

night blindness.

Defective night vision. When temporary may be due to a deficiency of vitamin A. When permanent may be due to diseases of the retina. . . .

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

nyctalope.

One who cannot see at night.

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

nyctaphobia.

An unnatural fear of night and darkness.

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

ocular.

1. Relating to the eye. 2. The lens of a microscope or other optical instruments nearest to the eye; an eyepiece.

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

optic.

Relating to the eye.

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

optician.

One who makes lenses or optical instruments. One who sells spectacles.

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