opˈtophone noun

An instrument that translates printed characters into arbitrary sounds, and so enables the blind to read ordinary type

optical activity noun (physics)

The ability of certain chemical compounds to rotate the plane of polarization of an already polarized beam of light in one direction or the other

optical art same as op art

optical character reader noun (computing)

A light-sensitive device for inputting data directly to a computer by means of optical character recognition (abbrev OCR)

optical character recognition noun (computing)

The scanning, identification and encoding of printed characters by photoelectric means (abbrev OCR)

optical computing noun

The technique of controlling the computer by pulses of light instead of by electronic means

optical disk noun (computing)

A disk that can be read from and often written to by a laser

optical-electronic device noun (physics)

An instrument used to locate weakly radiating sources by detecting their infrared emission

optical fibre noun

A thin strand of glass through which light waves may be transmitted, used eg in some communications systems, fibre optics, etc

optical illusion noun

1. Something that has an appearance which deceives the eye
2. A misunderstanding caused by such a deceptive appearance

optical maser noun

Laser

optical microscope, telescope noun

A microscope or telescope that operates by the direct perception of light from the object viewed, as opposed to an electron microscope or radio telescope

optical pumping noun (physics)

The act of stimulating a population inversion for a particular energy transition in a laser using an external light source of suitable frequency

optical spectrum noun (physics)

The visible radiation emitted from a source separated into its component frequencies

optical splitter noun (telecommunications)

A device for separating signals into two or more channels, eg optical fibres

optical tweezers plural noun

An instrument used to manipulate microscopic objects by means of highly focused laser light

optic axis noun

1. The axis of the eye, a line through the middle of the pupil and the centre of the eye
2. The line which passes through the centre of curvature of a lens or mirror surface so that the rays are neither reflected nor refracted (also called principal axis)
3. In a doubly refracting crystal, a direction in which no double refraction occurs

optic disc noun

The blind spot of the eye

optic lobe noun

The part of the mid-brain concerned with sight

optic nerve noun

The second cranial nerve, responsible for the sense of vision, which transmits information from the retina of the eye to the visual cortex of the brain

optic thalamus noun (anatomy)

An older name for thalamus