Perceptual adaptation is the means by which the brain accounts for the differences that the subject may witness, particularly alterations in the visual field. For example, if an individual's visual field is altered forty five degrees left, the brain accounts for the difference allowing the individual to function normally.
Perceptual adaptation is where the brain adapts to the information that it receives. The brain plays a crucial role in the inner workings of vision. The world that one perceives is processed via the brain. Images sensed through the eyes are relayed to the visual cortex of the brain, and if vision is altered slightly, the brain accounts for the difference and will allow one to perceive the world as "normal." For example, the brain responds to a change in perceived vision when glasses are worn to distort images any subject sees by forty five degrees. Over time, the brain processes the acute difference as normal. As a result of this adaptation the brain makes to this difference in perception, the subject, with the glasses, is able to perform daily tasks as before the glasses were applied. Contrary to perceptual adaptation, if the distortion in vision is repealed, then the brain will perceive images as when the distortion was first applied. 
Psychologist George M. Stratton conducted, in the 1890s, experiments in which he tested the theory of perceptual adaptation. In one experiment, he wore a reversing glasses for 21½ hours over three days, with no change in his vision. After removing the glasses, "normal vision was restored instantaneously and without any disturbance in the natural appearance or position of objects."
On a later experiment, Stratton wore the glasses for eight whole days. By day four, the images seen through the instrument were still upside down. However, on day five, images appeared upright until he concentrated on them; then they became inverted again. By having to concentrate on his vision to turn it upside down again, especially when he knew images were hitting his retinas in the opposite orientation as normal, Stratton deduced his brain had reprocessed his vision and adapted to the changes in vision.
Potential alterations to the visual field
The visual field can be altered in many ways. The various ways that it can be altered is by angles, or by orientation. Optometrists alter the visual field by altering angles (i.e. fashion the subject with glasses that construe the visual field by differing angles). George Stratton conducted experiments where the visual field was altered by an angle of forty five degrees and his brain was able to adapt to the change and perceive the world as normal. Also, the field can be altered making the subject see the world upside down. But, as the brain adjusts to the change, the world appears "normal."
Effectiveness in compensating for alterations in the visual field
An altered visual field does not adversely affect one’s life. Our perceptual adaptation allows us to adapt to the world and live life as normal. Therefore, with an altered visual field, the limits are nonexistent. One is able to do whatever they please without limitations. In some extreme experiments, psychologists have tested to see if a pilot can fly a plane with altered vision. All of the pilots that were fitted with the goggles that alter their vision were able to safely navigate the aircraft with ease.
Perceptual adaptation is an element that has been researched extensively by George Stratton. All of his experiments supported the theory of perceptual adaptation. Perceptual adaptation is a theory that proposes the notion that our brain and senses collaborate. Our vision can be altered, but our brain corrects this alteration to seem correct. Our brain allows us to live a normal life with an altered perception of a normal life.
- Myers, David G. (2007). Exploring Psychology in Modules (7th ed.). New York: Worth Publishers. ISBN 978-1-4292-0589-4.[page needed]
- Stratton, George M. (1896). "Some preliminary experiments on vision without inversion of the retinal image". Psychological Review 3 (6): 611–7. doi:10.1037/h0072918.
- Cullari, Salvatore (21 Mar. 1997). "Re: Upside Down Glasses?". MadSci Network.
- Miyauchi, Satoru; Egusa, Hiroyuki; Amagase, Masahiro; Sekiyama, Kaoru; Imaruoka, Toshihide; Tashiro, Takara (2004). "Adaptation to left–right reversed vision rapidly activates ipsilateral visual cortex in humans". Journal of Physiology-Paris 98 (1-3): 207–19. doi:10.1016/j.jphysparis.2004.03.014. PMID 15477033.