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Stereopsis recovery, also recovery from stereoblindness, is the phenomenon of a stereoblind person gaining partial or full ability of stereo vision (stereopsis). It has long been established state of the art that the therapeutic treatment of stereoblind patients should aim at recovering stereo vision as far as possible in very young children, as well as in patients who had acquired but lost their ability for stereopsis due to a medical condition. In contrast, this aim has normally not been present in the treatment of those who missed out on learning stereopsis during their first few years of life. In fact, the acquisition of binocular and stereo vision was long thought to be impossible unless the person acquired this skill during a critical period in infancy and early childhood.〔See for example: 〕 This hypothesis normally went unquestioned and has formed the basis for the therapeutic approaches to binocular disorders for decades. It has been put in doubt in recent years. In particular since studies on stereopsis recovery began to appear in scientific journals and it became publicly known that neuroscientist Susan R. Barry achieved stereopsis well into adulthood, that assumption is in retrospect considered to have held the status of a scientific dogma.〔Susan R. Barry (2009) ''Fixing My Gaze: A Scientist's Journey into Seeing in Three Dimensions''. New York: Basic Books. ISBN 978-0-465-02073-7〕〔"() The book's main contribution, however, is exposing the wrong-headed dogma that acuity and binocular vision can be restored only during a critical developmental period." —''New England Journal of Medicine''. (See introductory pages of: Susan R. Barry (2009) ''Fixing My Gaze.)〕〔"() Part memoir and part science, ''Fixing My Gaze'' is a fitting tribute to the determination of a patient and her optometrist in challenging conventional wisdom and dogma." —''Journal of Behavioral Optometry''. (See introductory pages of: Susan R. Barry (2009) ''Fixing My Gaze.)〕 Very recently, there has been a rise in scientific investigations into stereopsis recovery in adults and youths who have had no stereo vision before. While it has now been shown that an adult ''may'' gain stereopsis, it is currently not yet possible to predict how likely a stereoblind person is to do so, nor is there general agreement on the best therapeutic procedure. Also the possible implications for the treatment of children with infantile esotropia are still under study. == Clinical management of strabismus and stereoblindness == In cases of acquired strabismus with double vision (diplopia), it is long-established state of the art to aim at curing the double vision and at the same time recovering a patient's earlier ability for stereo vision. For example a patient may have had full stereo vision but later had diplopia due to a medical condition, losing stereo vision. In this case, medical interventions, including vision therapy and strabismus surgery, may remove the double vision and recover the stereo vision which had temporarily been absent in the patient. Also when children with congenital (infantile) strabismus (e.g. infantile esotropia) receive strabismus surgery within the first few years or two of their life, this goes along with the hope that they may yet develop their full potential for binocular vision including stereopsis. In contrast, in a case where a child's eyes are straightened surgically after the age of about five or six years and the child had no opportunity to develop stereo vision in early childhood, normally the clinical expectation is that this intervention will lead to cosmetic improvements but not to stereo vision. Conventionally, no follow-up for stereopsis was performed in such cases. For instance, one author summarized the accepted scientific view of the time with the words: "Stereopsis will never be obtained unless amblyopia is treated, the eyes are aligned, and binocular fusion and function are achieved before the critical period for stereopsis ends. Clinical data suggest that this occurs before 24 months of age,() but we do not know exactly when it occurs, because crucial pieces of basic science information are missing." For purposes of illustration, reference is made to a book of doctors' handouts for patients, written for the general public and published in 2002, which summarizes the limitations in the terms in which they, at the time, were fully accepted as medical state of the art as follows: "If an adult has a childhood strabismus that was never treated, it is too late to improve any amblyopia or depth perception, so the goal may be simply cosmetic – to make the eyes appear to be properly aligned – though sometimes treatment does enlarge the extent of side vision."〔Melvin L. Rubin, Lawrence A. Winograd: ''Taking Care of Your Eyes: A Collection of the Patient Information Handouts Used by America's Leading Eye Doctors'', Triad Records (September 2002), ISBN 978-0937404614〕 It has only been accepted very recently that the therapeutic approach was based on an unquestioned notion that has, since, been referred to as "myth" or "dogma".〔 Recently, however, stereopsis recovery is known to have occurred in a number of adults. While this has in some cases occurred after visual exercises or spontaneous visual experiences, recently also the medical community's view of strabismus surgery has become more optimistic with regard to outcomes in terms of binocular function and possibly stereopsis. As one author states: :"The majority of adults will experience some improvement in binocular function after strabismus surgery even if the strabismus has been longstanding. Most commonly this takes the form of an expansion of binocular visual fields; however, some patients may also regain stereopsis." Scientific investigations on residual neural plasticity in adulthood now also include studies on the recovery of stereopsis. Now it is a matter of active scientific investigation under which conditions and to which degree binocular fusion and stereo vision can be acquired in adulthood, especially if the person is not known to have had any preceding experience of stereo vision, and how outcomes may depend on the patient's history of therapeutic interventions. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Stereopsis recovery」の詳細全文を読む スポンサード リンク
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