op-, opt-, optico-, opsi-, opso-, -opia, -ops, -opsia, -opsis, -opsy, -optic, -opic, -opy +

The technology of optical instruments and apparatus.

1. The style of type used on an eye chart.
2. A standardized symbol for testing vision.
3. Types used to determine visual acuity when different sizes are presented to a person and the smallest size the person can reliably identify determines the person's level of achievement.

A condition of normal vision and alignment of the eyes.

1. A condition in which the visual image is seen to move rapidly from side to side or vertically.
2. The subjective sensation of oscillation of objects viewed.

Abnormal acuteness, or sharpness, of sight.

1. In medicine, the pathologic continuance or recurrence of a visual sensation after the stimulus is gone.
2. Abnormal recurring visual hallucinations.

1. Including everything visible in one view.
2. Permitting the viewing of all parts or elements.

1. A building; such as, a prison, a hospital, a library, etc., arranged so that all parts of the interior are visible from a single position.
2. A circular prison with cells distributed around a central surveillance station.

A condition in which the hearing of certain sounds gives rise to a subjective sensation of color or the condition of eliciting color sensations by acoustic stimulation; also synesthesia.

1. Relating to vision with the normal eyes in bright light; for example, day vision.
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.

An appearance as of sparks, or flashes, resulting from retinal irritation.

Vision with eyes that are adapted to normal bright daylight.

A poet who is expressing his thoughts about death which is the fate of every human being.

The formation of more than one image of an object on the retina; multiple vision.

1. A form of farsightedness occurring after middle age, caused by a diminished elasticity of the crystalline lens.
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".