Optical Axis and Visual Axis
The optical axis is the centre of a lens where light travels through and is not bent. The visual axis is where light travels through the eye to the retina and is essentially understood to not be bent.
Sometimes glasses are given with the optical axis shifted away from the visual axis. This creates a prismatic effect. Prisms can be used to diagnose and treat binocular vision and other orthoptics problems which cause diplopia such as:
- Positive and negative fusion problems
- Positive relative accommodation and negative relative accommodation problems
Read more about this topic: Eyeglass Prescription
Famous quotes containing the words optical, axis and/or visual:
“People who have realized that this is a dream imagine that it is easy to wake up, and are angry with those who continue sleeping, not considering that the whole world that environs them does not permit them to wake. Life proceeds as a series of optical illusions, artificial needs and imaginary sensations.”
—Alexander Herzen (1812–1870)
“A book is not an autonomous entity: it is a relation, an axis of innumerable relations. One literature differs from another, be it earlier or later, not because of the texts but because of the way they are read: if I could read any page from the present time—this one, for instance—as it will be read in the year 2000, I would know what the literature of the year 2000 would be like.”
—Jorge Luis Borges (1899–1986)
“Nowadays people’s visual imagination is so much more sophisticated, so much more developed, particularly in young people, that now you can make an image which just slightly suggests something, they can make of it what they will.”
—Robert Doisneau (b. 1912)