Acquired vision
Encyclopedia
Recovery from blindness is the phenomenon of a blind
person gaining the ability to see, usually as a result of medical treatment. As a thought experiment
, the phenomenon is usually referred to as Molyneux's Problem
. The first published human case was reported in 1728 by the Surgeon William Cheselden
. Patients who experience dramatic recovery from blindness experience significant to total Agnosia
, having serious confusion with their visual perception
.
as a thought experiment
, in order to describe the knowledge gained from senses, and
question the correlation between different senses.
John Locke
, an 18th century philosopher, speculated that if a blind person developed vision, he would not at first connect his idea of a shape with the sight of a shape. That is, if asked which was the cube and which was the sphere, he would not be able to do so, or even guess.
The question was originally posed to him by philosopher William Molyneux
, whose wife was blind:
In 1709, in “A New Theory of Vision,” George Berkeley
also concluded that there was no necessary connection between a tactile world and a sight world—that a connection between them could be established only on the basis of experience.
He speculated:
This thought experiment
(it was a thought experiment at the time) outlines the debate between rationalism
and empiricism
; to what degree our knowledge of the world comes from reason or experience.
Before the first known human cases, some tests were done rearing animals in darkness, to deny them vision for months or years, then discover what they see when given light. A. H. Reisen found severe behavioural losses in such experiments; but they might have been due to degeneration of the retina.
The first known case of published recovery from blindness is in 1728, of a blind 13 year old boy by William Cheselden
. Cheselden presented the celebrated case of a the boy of thirteen who gained his sight after removal of the lenses rendered opaque by cataract from birth.
Despite his youth, the boy encountered profound difficulties with the simplest visual perceptions.
Described by Cheselden:
recounts the story of Virgil, a man who saw very little until having cataract
surgery at age 50. Virgil's subsequent behavior was that of a "mentally blind" person —someone who sees but can't decipher what's out there; he would act as if he were still blind. Often confused, Virgil rapidly sank into depression. About 4 months after his surgery, he died of pneumonia.
described a patient, Sidney Bradford
, a 52 year-old who gained vision from corneal grafts to both eyes. No experimental psychologist was informed of the case until after the corneal grafting took place.
His operation was able to reveal idiosyncrasies of the human visual system. For example, not having grown up with vision, Bradford did not perceive the ambiguity of the Necker cube
. Nor was he able to interpret the perspective
of two-dimensional art.
Nevertheless, he could accurately judge the distance to objects in the same room, having been familiar with these distances before regaining sight by virtue of having walked them. In a similar analogy between vision and sightless (touch-only) experience, Bradford was able to visually read the time on the ward clock
just after his operation. Before surgery Bradford was a skilled machinist
, but upon gaining vision, he became confused and unable to work. He committed suicide 2 years after his operation.
The case history published in the Quarterly Journal of Psychology in 1963.
in 2000, at 46, after Corneal transplantation and a pioneering stem cell
procedure by San Francisco ophthalmologist Daniel Goodman.
May had a stem-cell transplant in his right eye in 2001 when he was 43, after 40 years of blindness. He reportedly has adapted well to his recovered vision.
The effect of visual loss has an impact in the development of the visual cortex of the brain. The visual impairment causes the occipital lobe to lose its sensitivity in perceiving spatial processing. Sui and Morley (2008) proposed that after 7 days of visual deprivation, a potential decrease in vision may occur. They also found an increasing visual impairment with deprivation after 30 days and 120 days. This study suggests that the function of the brain depends on visual input. Michael lost his eyesight at age 3, when his vision was still not fully developed to distinguish shapes, drawings or images clearly. It would be difficult for him to be able to describe the world compared to a normal sighted person. For instance, Michel would have trouble differentiating complex shapes, dimension and orientations of objects. Hannan (2006) hypothesized that the temporal visual cortex uses prior memory and experiences to make sense of shapes, colours and forms. She proposed that the long term effect of blindness in the visual cortex is the lack of recognition of spatial cues.
At 3 years of age, Michael’s vision had still not reached the acuity of an adult person, so his brain was still not completely exposed to all possible clarity of images and light of the environment. His brain lacked the full picture of the world to be able to describe its beauty. This made it difficult for Michael to lead a normal daily life. Cohen et al. (1997) suggested that early blindness causes a poor development of the visual cortex with the result of a decrease in somatosensory development. This study proposed that Michael’s long term blindness affects his ability to distinguish in between faces of males and females, and to recognize pictures and images. In spite of the surgery on his right eye, his newly regained vision, after blindness of forty years, is not fully recovered. Thinus-Blanc and Gaunet (1997) suggest that early blinded people show limited ability in spatial representation. Michael still struggles to identify pictures or illustrations. The impairment of his visual cortex, due to the loss of his vision at a very early age, resulted in visual cortex cells that are not used to the stimuli in his surroundings. Cohen et al. (1997) proposed that in their early age, blinded subjects developed strong motivations to tactile discrimination tasks. Michael’s early blindness benefited him so far; he developed very precise senses of hearing and touch.
The fact that Michael lost his sight at an early age affected his development, critical period and played a large role in his impaired development after surgery years later thus, impairing his depth perception and visual acuity.
In 2006, journalist Robert Kurson
wrote a book on May, Crashing Through, expanded from an article he did for Esquire , which is being adapted into a motion picture. Crashing Through was released on May 15, 2007.
infection resulted in anoxia
, and ultimately cost Jennings his vision again.
Corneal grafts are also becoming more common.
More recently, another condition called aniridia
has been treated with reconstructive surgery using the membrane from the amniotic sac
that surrounds a fetus combined with stem cell transplantation into the eye.
In 2003, three people were successfully implanted with a permanent "retinal prosthesis" by researchers at the University of Southern California
. Each patient wore spectacles with miniature video cameras that transmitted signals to a 4-mm-by-5-mm retinal implant via a wireless receiver embedded behind the ear.
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
person gaining the ability to see, usually as a result of medical treatment. As a thought experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
, the phenomenon is usually referred to as Molyneux's Problem
Molyneux's Problem
Molyneux's problem is a thought experiment in philosophy concerning immediate recovery from blindness.It was first formulated by William Molyneux, and notably referenced in John Locke's An Essay Concerning Human Understanding....
. The first published human case was reported in 1728 by the Surgeon William Cheselden
William Cheselden
William Cheselden was an English surgeon and teacher of anatomy and surgery, who was influential in establishing surgery as a scientific medical profession.-Life:...
. Patients who experience dramatic recovery from blindness experience significant to total Agnosia
Agnosia
Agnosia is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss...
, having serious confusion with their visual perception
Visual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
.
As a thought experiment
The phenomenon has often been presented in empiricismEmpiricism
Empiricism is a theory of knowledge that asserts that knowledge comes only or primarily via sensory experience. One of several views of epistemology, the study of human knowledge, along with rationalism, idealism and historicism, empiricism emphasizes the role of experience and evidence,...
as a thought experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
, in order to describe the knowledge gained from senses, and
question the correlation between different senses.
John Locke
John Locke
John Locke FRS , widely known as the Father of Liberalism, was an English philosopher and physician regarded as one of the most influential of Enlightenment thinkers. Considered one of the first of the British empiricists, following the tradition of Francis Bacon, he is equally important to social...
, an 18th century philosopher, speculated that if a blind person developed vision, he would not at first connect his idea of a shape with the sight of a shape. That is, if asked which was the cube and which was the sphere, he would not be able to do so, or even guess.
The question was originally posed to him by philosopher William Molyneux
William Molyneux
William Molyneux FRS was an Irish natural philosopher and writer on politics.He was born in Dublin to Samuel Molyneux , lawyer and landowner , and his wife, Anne, née Dowdall. The second of five children, William Molyneux came from a relatively prosperous Anglican background...
, whose wife was blind:
Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal, and nighly of the same bigness, so as to tell, when he felt one and the other, which is the cube, which is the sphere. Suppose then the cube and the sphere placed on a table, and the blind man made to see: query, Whether by his sight, before he touched them, he could now distinguish and tell which is the globe, which the cube? To which the acute and judicious proposer answers: ‘Not. For though he has obtained the experience of how a globe, and how a cube, affects his touch; yet he has not yet attained the experience, that what affects his touch so or so, must affect his sight so or so…’
In 1709, in “A New Theory of Vision,” George Berkeley
George Berkeley
George Berkeley , also known as Bishop Berkeley , was an Irish philosopher whose primary achievement was the advancement of a theory he called "immaterialism"...
also concluded that there was no necessary connection between a tactile world and a sight world—that a connection between them could be established only on the basis of experience.
He speculated:
the objects to which he had hitherto used to apply the terms up and down, high and low, were such as only affected or were in some way perceived by touch; but the proper objects of vision make a new set of ideas, perfectly distinct and different from the former, and which can in no sort make themselves perceived by touch (sect. 95).
This thought experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
(it was a thought experiment at the time) outlines the debate between rationalism
Rationalism
In epistemology and in its modern sense, rationalism is "any view appealing to reason as a source of knowledge or justification" . In more technical terms, it is a method or a theory "in which the criterion of the truth is not sensory but intellectual and deductive"...
and empiricism
Empiricism
Empiricism is a theory of knowledge that asserts that knowledge comes only or primarily via sensory experience. One of several views of epistemology, the study of human knowledge, along with rationalism, idealism and historicism, empiricism emphasizes the role of experience and evidence,...
; to what degree our knowledge of the world comes from reason or experience.
First case
There are many stories or anecdotes of the phenomenon, preceding the first documented case, including one from the year 1020, of a man of thirty operated upon in Arabia.Before the first known human cases, some tests were done rearing animals in darkness, to deny them vision for months or years, then discover what they see when given light. A. H. Reisen found severe behavioural losses in such experiments; but they might have been due to degeneration of the retina.
The first known case of published recovery from blindness is in 1728, of a blind 13 year old boy by William Cheselden
William Cheselden
William Cheselden was an English surgeon and teacher of anatomy and surgery, who was influential in establishing surgery as a scientific medical profession.-Life:...
. Cheselden presented the celebrated case of a the boy of thirteen who gained his sight after removal of the lenses rendered opaque by cataract from birth.
Despite his youth, the boy encountered profound difficulties with the simplest visual perceptions.
Described by Cheselden:
When he first saw, he was so far from making any judgment of distances, that he thought all object whatever touched his eyes (as he expressed it) as what he felt did his skin, and thought no object so agreeable as those which were smooth and regular, though he could form no judgment of their shape, or guess what it was in any object that was pleasing to him: he knew not the shape of anything, nor any one thing from another, however different in shape or magnitude; but upon being told what things were, whose form he knew before from feeling, he would carefully observe, that he might know them again;
Virgil
In his book, An Anthropologist On Mars (1995), neurologist Oliver SacksOliver Sacks
Oliver Wolf Sacks, CBE , is a British neurologist and psychologist residing in New York City. He is a professor of neurology and psychiatry at Columbia University, where he also holds the position of Columbia Artist...
recounts the story of Virgil, a man who saw very little until having cataract
Cataract
A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...
surgery at age 50. Virgil's subsequent behavior was that of a "mentally blind" person —someone who sees but can't decipher what's out there; he would act as if he were still blind. Often confused, Virgil rapidly sank into depression. About 4 months after his surgery, he died of pneumonia.
Sidney Bradford (S.B.)
In 1974, Richard GregoryRichard Gregory
Richard Langton Gregory, CBE, MA, D.Sc., FRSE, FRS was a British psychologist and Emeritus Professor of Neuropsychology at the University of Bristol.-Life and career:...
described a patient, Sidney Bradford
Sidney Bradford
Sidney Bradford went blind at 10 months of age but regained sight on both eyes after a cornea transplant at the age of 52. He was the subject of many scientific studies of perception by neuropsychologist Richard Gregory....
, a 52 year-old who gained vision from corneal grafts to both eyes. No experimental psychologist was informed of the case until after the corneal grafting took place.
His operation was able to reveal idiosyncrasies of the human visual system. For example, not having grown up with vision, Bradford did not perceive the ambiguity of the Necker cube
Necker cube
The Necker Cube is an optical illusion first published as a rhomboid in 1832 by Swiss crystallographer Louis Albert Necker.-Ambiguity:The Necker Cube is an ambiguous line drawing....
. Nor was he able to interpret the perspective
Perspective (graphical)
Perspective in the graphic arts, such as drawing, is an approximate representation, on a flat surface , of an image as it is seen by the eye...
of two-dimensional art.
Nevertheless, he could accurately judge the distance to objects in the same room, having been familiar with these distances before regaining sight by virtue of having walked them. In a similar analogy between vision and sightless (touch-only) experience, Bradford was able to visually read the time on the ward clock
Clock
A clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece...
just after his operation. Before surgery Bradford was a skilled machinist
Machinist
A machinist is a person who uses machine tools to make or modify parts, primarily metal parts, a process known as machining. This is accomplished by using machine tools to cut away excess material much as a woodcarver cuts away excess wood to produce his work. In addition to metal, the parts may...
, but upon gaining vision, he became confused and unable to work. He committed suicide 2 years after his operation.
The case history published in the Quarterly Journal of Psychology in 1963.
Michael May
Michael G. "Mike" May (born 1954) was blinded by a chemical explosion at the age of 3 but regained partial visionVisual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
in 2000, at 46, after Corneal transplantation and a pioneering stem cell
Stem cell
This article is about the cell type. For the medical therapy, see Stem Cell TreatmentsStem cells are biological cells found in all multicellular organisms, that can divide and differentiate into diverse specialized cell types and can self-renew to produce more stem cells...
procedure by San Francisco ophthalmologist Daniel Goodman.
May had a stem-cell transplant in his right eye in 2001 when he was 43, after 40 years of blindness. He reportedly has adapted well to his recovered vision.
- May still has no intuitive grasp of depth perception. As people walk away from him, he perceives them as literally shrinking in size
- problems distinguishing male from female faces, and recognizing emotional expressionEmotional expressionIn psychology, emotional expression is observable verbal and nonverbal behaviour that communicates emotion. Emotional expression can occur with or without self-awareness...
s on unfamiliar faces.
The effect of visual loss has an impact in the development of the visual cortex of the brain. The visual impairment causes the occipital lobe to lose its sensitivity in perceiving spatial processing. Sui and Morley (2008) proposed that after 7 days of visual deprivation, a potential decrease in vision may occur. They also found an increasing visual impairment with deprivation after 30 days and 120 days. This study suggests that the function of the brain depends on visual input. Michael lost his eyesight at age 3, when his vision was still not fully developed to distinguish shapes, drawings or images clearly. It would be difficult for him to be able to describe the world compared to a normal sighted person. For instance, Michel would have trouble differentiating complex shapes, dimension and orientations of objects. Hannan (2006) hypothesized that the temporal visual cortex uses prior memory and experiences to make sense of shapes, colours and forms. She proposed that the long term effect of blindness in the visual cortex is the lack of recognition of spatial cues.
At 3 years of age, Michael’s vision had still not reached the acuity of an adult person, so his brain was still not completely exposed to all possible clarity of images and light of the environment. His brain lacked the full picture of the world to be able to describe its beauty. This made it difficult for Michael to lead a normal daily life. Cohen et al. (1997) suggested that early blindness causes a poor development of the visual cortex with the result of a decrease in somatosensory development. This study proposed that Michael’s long term blindness affects his ability to distinguish in between faces of males and females, and to recognize pictures and images. In spite of the surgery on his right eye, his newly regained vision, after blindness of forty years, is not fully recovered. Thinus-Blanc and Gaunet (1997) suggest that early blinded people show limited ability in spatial representation. Michael still struggles to identify pictures or illustrations. The impairment of his visual cortex, due to the loss of his vision at a very early age, resulted in visual cortex cells that are not used to the stimuli in his surroundings. Cohen et al. (1997) proposed that in their early age, blinded subjects developed strong motivations to tactile discrimination tasks. Michael’s early blindness benefited him so far; he developed very precise senses of hearing and touch.
The fact that Michael lost his sight at an early age affected his development, critical period and played a large role in his impaired development after surgery years later thus, impairing his depth perception and visual acuity.
In 2006, journalist Robert Kurson
Robert Kurson
Robert Kurson is an American author, best known for his 2004 bestselling book, Shadow Divers, the true story of two Americans who discover a World War II German U-boat sunk 60 miles off the coast of New Jersey....
wrote a book on May, Crashing Through, expanded from an article he did for Esquire , which is being adapted into a motion picture. Crashing Through was released on May 15, 2007.
Shirl Jennings
Shirl Jennings (1940–2003) was blinded by illness as a young boy. Experimental surgery in 1991 partially restored his vision, but like Bradford and May, Jennings found the transition to sightedness difficult. In 1992, a pneumoniaPneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
infection resulted in anoxia
Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...
, and ultimately cost Jennings his vision again.
Modern history
In 1960, Maurice von Senden restored vision to 65 patients with congenital cataracts.Corneal grafts are also becoming more common.
More recently, another condition called aniridia
Aniridia
Aniridia is the absence of the iris. Aniridia usually involves both eyes. It can be congenital or caused by a penetrant injury. Isolated aniridia is a congenital disorder which is not limited to a defect in iris development, but is a panocular condition with macular and optic nerve hypoplasia,...
has been treated with reconstructive surgery using the membrane from the amniotic sac
Amniotic sac
The amniotic sac is the sac in which the fetus develops in amniotes. It is a tough but thin transparent pair of membranes, which hold a developing embryo until shortly before birth. The inner membrane, the amnion, contains the amniotic fluid and the fetus. The outer membrane, the Chorion,...
that surrounds a fetus combined with stem cell transplantation into the eye.
In 2003, three people were successfully implanted with a permanent "retinal prosthesis" by researchers at the University of Southern California
University of Southern California
The University of Southern California is a private, not-for-profit, nonsectarian, research university located in Los Angeles, California, United States. USC was founded in 1880, making it California's oldest private research university...
. Each patient wore spectacles with miniature video cameras that transmitted signals to a 4-mm-by-5-mm retinal implant via a wireless receiver embedded behind the ear.
Christianity
The following account of visual agnosia from a sudden recovery of sight is from the Gospel of St. Mark, Chapter 8: "And he cometh to Bethsaida; and they bring a blind man unto him, and besought him to touch him. And he took the blind man by the hand, and led him out of the town; and when he had spit on his eyes, and put his hands upon him, he asked him if he saw ought. And he looked up, and said, I see men as trees, walking. After that he put his hands again upon his eyes, and made him look up: and he was restored, and saw every man clearly."See also
- blindsightBlindsightBlindsight is a phenomenon in which people who are perceptually blind in a certain area of their visual field demonstrate some response to visual stimuli...
- when a blind person can perceive visual stimuli unconsciously. - Hand-eye coordination
- Mike May who recovered his vision late in life after losing it at the age of 3.
External links
- "Giving Sight to the Blind" lecture by Brian WandellBrian WandellBrian A. Wandell is the Isaac and Madeline Stein Family Professor at Stanford University, where he was a former Chair of the Psychology Department....
at Stanford UniversityStanford UniversityThe Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...