op-, opt-, optico-, opsi-, opso-, -opia, -ops, -opsia, -opsis, -opsy, -optic, -opic, -opy
(Greek: eye[s]; sight; see, vision)
2. A circular prison with cells distributed around a central surveillance station.
3. Movie theaters that deliver all kinds of entertainment and instructional programs, by transmitting virtual reality directly to the sensory systems of spectators, including odors, movement sensation, etc.
2. Pertaining to vision in the light; said of the eyes which have become light-adapted.
3. Sometimes applicable to seeing what appears to be sparks in front of the eyes.
A person can recognize the transition from photopic vision to scotopic (night) vision with the disappearance of color perception, which is replaced by shades of black and white.
2. The physiological loss of accommodation in the eyes in advancing age, said to begin when the near point has receded beyond 22 cm (9 inches).
3. The loss of the eye's ability to change focus to see near objects.
4. Eyesight characteristic of older people.
The reasons for this loss of the power of accommodation are not yet fully known. It is conventionally said to be a result of the lenses of the eyes becoming less elastic with time.
Presbyopia is associated with aging; however, it happens with everyone. The first sign is often the necessity to hold reading material farther away in order to be able to focus on the contents.
The term presbyopia is said to come from the Greek for "elderly vision".
2. Visual agnosia, or the inability to recognize objects by sight.
The subject sees the object, but cannot identify it; because of a lesion in the area of the occipital cortex.
It is broken down by the action of dim light into retinal (layer of neurons, or nerve cells, that line the back of the eye) and opsin (several compounds that form the protein component of the light-sensitive retina pigment).
2. Loss of color perception, with the ability to discern only shades of black and white.
3. Vision when the eye is adapted to the dark; also: night vision, rod vision, and twilight vision.
2. The power of discerning what is not visible to the physical eye, or of foreseeing future events; such as are of a disastrous kind, the capacity of a seer or prophetic vision.