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==Criticisms of the Bates Method==
==Criticisms of the Bates Method==
===Theories of accommodation/focusing and refractive errors===
===Theories of accommodation/focusing and refractive errors===
Critics of the Bates Method reject the theory that human eyes accommodate, or focus, due to elongation of the eyeball caused by “squeezing” of the extraocular muscles, as has been claimed to happen in some animals. Critics of the Bates Method instead support the mainstream theory set forth by [[Hermann von Helmholtz]] that human eyes accommodate, or focus, due to the actions of the ciliary muscle (an intraocular muscle) and zonules changing the shape of the crystalline lens. To support this theory, critics of the Bates Method point to the action of various cycloplegic agents which temporarily paralyze accommodation by relaxing the ciliary muscle but leave the extraocular muscles, which control eye movements, unaffected. Modern equipment, not available to Bates, has made possible the observation of the eye in great detail. Modern observations have shown the lens changing shape when the eye accommodates. <ref name="pollack"/> Elwin Marg, writing in [[1952]] points out that "it would take about one millimeter change in axial length of the eyeball for each 3 diopters change of refractive power. Hence, a youth accommodating 15 D would shorted his globe by ''five millimeters.''" He continues: "to the writer's knowledge, no corresponding anterior-posterior corneal movement has ever been reported." <ref name=Marg>{{cite journal | author=Marg, E. | title="Flashes" of clear vision and negative accommodation with reference to the Bates Method of visual training. | journal=Am J Opt Arch Am Ac Opt | year=1952 | volume=29 | issue=4 | pages=167-84}}</ref>
Critics of the Bates Method reject the theory that human eyes accommodate, or focus, due to elongation of the eyeball caused by “squeezing” of the extraocular muscles, as has been claimed to happen in some animals. Critics of the Bates Method instead support the mainstream theory set forth by [[Hermann von Helmholtz]] that human eyes accommodate, or focus, due to the actions of the ciliary muscle (an intraocular muscle) and zonules changing the shape of the crystalline lens. To support this theory, critics of the Bates Method point to the action of various cycloplegic agents which temporarily paralyze accommodation by relaxing the ciliary muscle but leave the extraocular muscles, which control eye movements, unaffected. Modern equipment, not available to Bates, has made possible the observation of the eye in great detail. Modern observations have shown the lens changing shape when the eye accommodates. <ref name="pollack"/> Elwin Marg, writing in [[1952]] points out that "it would take about one millimeter change in axial length of the eyeball for each 3 diopters change of refractive power. Hence, a youth accommodating 15 D would shorted his globe by ''five millimeters.''" He continues: "to the writer's knowledge, no corresponding anterior-posterior corneal movement has ever been reported." <ref name=Marg>{{cite journal | author=Marg, E. | title=[brain.berkeley.edu/pub/1952%20April%20Flashes%20of%20Clear%20Vision.pdf | "Flashes" of clear vision and negative accommodation with reference to the Bates Method of visual training.] | journal=Am J Opt Arch Am Ac Opt | year=1952 | volume=29 | issue=4 | pages=167-84}}</ref>


The concept that relaxing the extraocular muscles can reliably or predictably reduce refractive error has not been substantiated by patients whose muscles are loosened during [[strabismus surgery]]. Although small refractive changes may occur following this type of muscle loosening surgery ([[recession]]), these alterations are generally small, clinically insignificant, transient, and occur in both directions (stronger and weaker). <ref name="Preslan">{{cite journal | author = Preslan M, Cioffi G, Min Y | title = Refractive error changes following strabismus surgery. | journal = J Pediatr Ophthalmol Strabismus | volume = 29 | issue = 5 | pages = 300-4 | year = | id = PMID 1432517}}</ref>
The concept that relaxing the extraocular muscles can reliably or predictably reduce refractive error has not been substantiated by patients whose muscles are loosened during [[strabismus surgery]]. Although small refractive changes may occur following this type of muscle loosening surgery ([[recession]]), these alterations are generally small, clinically insignificant, transient, and occur in both directions (stronger and weaker). <ref name="Preslan">{{cite journal | author = Preslan M, Cioffi G, Min Y | title = Refractive error changes following strabismus surgery. | journal = J Pediatr Ophthalmol Strabismus | volume = 29 | issue = 5 | pages = 300-4 | year = | id = PMID 1432517}}</ref>

Revision as of 01:31, 24 December 2007

The Bates method for better eyesight is an educational method developed by ophthalmologist William Horatio Bates, M.D., which aims to undo what Bates claimed are strained vision habits. Bates believed that various types of habitual strain originating in the mind are responsible not only for refractive errors which are usually compensated for with glasses (such as myopia, hyperopia, astigmatism, and presbyopia), but also for other abnormal eye conditions including strabismus, cataracts, glaucoma, amblyopia, conjunctivitis, blepharitis, and diseases of the optic nerve and retina.[1] Bates described his approach to helping patients relax such strain (and thus, he claimed, improve their sight) in a 1920 book entitled Perfect Sight Without Glasses, and in his monthly magazine entitled Better Eyesight (1919-1930).[2]

Because the copyrights are over 70 years old, the original version of Perfect Sight Without Glasses is available free on the internet (see links). In 1943 Bates' widow, Emily Bates, published an abridged version under the title Better Eyesight Without Glasses. These abridged versions removed many of the more controversial claims, such as "perfectly remembering black" being a suitable substitute for anaesthesia[3] or claims related to looking at the sun (see below).[4] But many Bates advocates prefer the original 1920 version, regarding it as the leading authority in explaining the method.[5][6]

Although many people claim to have been helped by the method, the efficacy of the Bates method is controversial. His theory that the eye does not focus by changing the power of the lens, but rather by elongating the eyeball, through use of the extraocular oblique muscles, was contradicted by mainstream ophthalmology and optometry of his day and is still today.[4][7]

"Natural vision teacher" Thomas R. Quackenbush defines the Bates method thus:

An educational program created by ophthalmologist William H. Bates, M.D., in which natural, correct vision habits—based on relaxation of the mind and body—are taught; optional self-healing activities and games are often included to accelerate integration and self-healing; commonly misunderstood as only "eye exercises"—even by many "Bates Method" teachers.[8]

Bates' theories

Accommodation by extraocular muscle squeezing

Accommodation is the process by which the eye increases optical power to maintain focus on the retina. So when the eyes change from viewing a distant object to a near object accommodation is taking place.

Bates rejected the orthodox view that accommodation was brought about by the action of the ciliary muscle on the eye's crystalline lens[9], and claimed that focus was maintained by varying elongation of the eyeball caused by the extraocular muscles. Bates claimed that the lens played no part in accommodation and reported that the extraocular muscles, and in particular the oblique muscles, squeeze the eyeball to obtain focus by elongation. Excessive tension of the recti muscles may also make, according to Bates, the eyeball too short (leading to hyperopia, and excessive tension of the oblique and recti muscles makes the eye astigmatic).

Bates regarded the superior and inferior oblique muscles as "the muscles of accommodation".[10]

Refractive errors due to extraocular muscle squeezing

Bates regarded the refractive state of the eye as variable and disregarded the notion that irreversible changes in the shape of the eyeball caused refractive errors. Instead, he stated that the shape of the eyeball responded instantly to the action of the extraocular muscles upon it.[11]

To Bates, refractive errors were due to a "loss of mental control" brought about by strain, specifically "strain of the mind". He claimed that straining to see at the near-point instantly shortened the eyeball, producing hypermetropia (farsightedness) in an eye with previously normal vision, and that straining to see at the far-point instantly lengthened the eyeball, producing myopia (nearsightedness) in an eye with previously normal vision.[12] At first this seems back-to-front, but by "straining to see at the near-point" Bates did not mean excessive close-work; he meant a mental effort to see close objects. He makes this clear in his chapter entitled 'Strain' where he says, "Mental strain of any kind always produces a conscious or unconscious eyestrain and if the strain takes the form of an effort to see, an error of refraction is always produced."[1]

In contrast to more recent research which has implicated heavy amounts of near-work as a contributing factor to the development of myopia[13][14], Bates emphasized that near-work and "overuse of the eyes" were not necessary to cause myopia, and claimed that he "made many dogs myopic by inducing them to strain to see a distant object."[12] He wrote: "The remedy is not to avoid either near work or distant vision, but to get rid of the mental strain which underlies the imperfect functioning of the eye at both points."[12]

Eyeglasses and contact lenses

Bates cited many disadvantages to eyeglasses made in his day, maintaining that they adversely affected color perception, contracted the field of vision, and caused dizziness and headaches when the wearer viewed objects off-axis. He wrote: "At their best it cannot be maintained that glasses are anything more than a very unsatisfactory substitute for normal vision."[15] Moreover, he maintained that the refractive condition of the eye is constantly changing, from day to day, hour to hour, and minute to minute; consequently, he said, the prescribing of corrective lenses can only ever be right at the time they are fitted, after which they encourage the eye to adjust to them (i.e. strain more) when they are too strong.

Bates said that those who have never worn glasses are generally cured of sight problems more easily than those who have, and recommended that patients who sought a cure completely discard their glasses from the outset. He acknowledged that it may not always be practical to do so, but said that continuing to wear them would delay the cure.[12] For those wanting to cure themselves without the personal help of a competent vision teacher, however, he emphasized that completely discarding glasses was a non-negotiable. From the chapter entitled 'Home Treatment': "It is absolutely necessary that the glasses be discarded. No half-way measures can be tolerated, if a cure is desired. Do not attempt to wear weaker glasses, and do not wear glasses for emergencies. Persons who are unable to do without glasses for all purposes are not likely to be able to cure themselves."[16]

Bates advocates believe that it is very harmful to wear glasses or contacts while viewing things which can be seen clearly without them. This is especially seen as a problem with contact lenses, since they are not normally removed when not needed.[17]

Bates' treatments

Bates wrote that "The ways in which people strain to see are infinite, and the methods used to relieve the strain must be almost equally varied"[12], emphasizing that no single approach would work for everyone, or even those whose sight problems are physiologically the same. His techniques are all methods designed to help dissociate strain from seeing (and are not, as is commonly misperceived, "exercises" in the sense of building muscle strength.)

Relaxation

Bates advocated relaxation and thinking relaxing thoughts as a way to reduce errors of refraction or squint: "When the disturbing thought is replaced by one that relaxes, the squint disappears, the double vision and the errors of refraction are corrected; and this is as true of abnormalities of long standing as of those produced voluntarily." Bates was of the opinion that the cause of "any error of refraction, of a squint, or of any other functional disturbance of the eye" was simply "wrong thoughts" and these "wrong thoughts" (and therefore the resulting pathology of the visual system) could be cured by relaxing thoughts. "In a fraction of a second the highest degrees of refractive error may be corrected, a squint may disappear, or the blindness of amblyopia may be relieved. If the relaxation is only momentary, the correction is momentary. When it becomes permanent, the correction is permanent."[1]

Central fixation

Central fixation was considered very important by Bates. Recognizing that only a very small part of the retina is capable of the highest resolution, he claimed that many people, when reading, allow the central fixation needed to maintain a sharp image to wander, so that they are attempting to focus using a low resolution part of the retina. He emphasized that good fixation is about relaxing and allowing the eyes to change gaze rapidly and naturally, rather than straining to fixate, which results in staring. Staring is the result of tension, according to Bates, and very bad.

Palming

Bates also advocated placing the hand over the eye in a way as to shut out all light and allow the eye and visual system to relax. This runs contrary to his other theory that sunlight was the "lifeblood of the eyes" and the more exposure to it, the better.[18]

Swinging

Swinging involves deliberate movements of the body with relaxed awareness of vision.

Sunlight exposure

Sunning involves looking at the sun through closed eyelids. Bates considered light to be the "lifeblood" of healthy eyes. See the discussion on safety below regarding this controversial aspect of his system.

Aldous Huxley and Margaret Corbett

The British writer Aldous Huxley was a famous advocate of the Bates method, claiming to have achieved successful results in his book entitled The Art of Seeing. Huxley was among the students of Margaret Corbett, A "Bates Practitioner", who trained with Dr. Bates in 1930 and later authored Help Yourself to Better Sight.

However, while Huxley undoubtedly believed his vision had improved, Bennett Cerf thought otherwise. In 1952 Cerf was reportedly present when Huxley spoke at a Hollywood banquet, wearing no glasses and apparently reading his paper from the lectern without difficulty:

"Then suddenly he faltered—and the truth became obvious. He wasn't reading his address—he had learned it by heart. To refresh his memory he brought it closer and closer to his eyes. When it was only an inch away he still couldn't read it, and had to fish for a magnifying glass in his pocket to make the typing visible to him. It was an agonizing moment."[19] (p. 241: quotes Bennett Cerf re Huxley's vision in 1952)

It should be noted that Bates believed that relapses do occur, even years after the improvement is obtained, which is consistent with his belief that refraction is variable.[20] Thus Cerf's account does not disprove Huxley's claimed success.

In 1941, Margaret Corbett was brought to trial in California on a charge of practicing medicine without a license, but was acquitted. Later, together with others, including Huxley, she successfully fought a State Bill which would have banned teaching methods of sight improvement and relaxation without a medical or ophthalmic license. [21]

Criticisms of the Bates Method

Theories of accommodation/focusing and refractive errors

Critics of the Bates Method reject the theory that human eyes accommodate, or focus, due to elongation of the eyeball caused by “squeezing” of the extraocular muscles, as has been claimed to happen in some animals. Critics of the Bates Method instead support the mainstream theory set forth by Hermann von Helmholtz that human eyes accommodate, or focus, due to the actions of the ciliary muscle (an intraocular muscle) and zonules changing the shape of the crystalline lens. To support this theory, critics of the Bates Method point to the action of various cycloplegic agents which temporarily paralyze accommodation by relaxing the ciliary muscle but leave the extraocular muscles, which control eye movements, unaffected. Modern equipment, not available to Bates, has made possible the observation of the eye in great detail. Modern observations have shown the lens changing shape when the eye accommodates. [22] Elwin Marg, writing in 1952 points out that "it would take about one millimeter change in axial length of the eyeball for each 3 diopters change of refractive power. Hence, a youth accommodating 15 D would shorted his globe by five millimeters." He continues: "to the writer's knowledge, no corresponding anterior-posterior corneal movement has ever been reported." [4]

The concept that relaxing the extraocular muscles can reliably or predictably reduce refractive error has not been substantiated by patients whose muscles are loosened during strabismus surgery. Although small refractive changes may occur following this type of muscle loosening surgery (recession), these alterations are generally small, clinically insignificant, transient, and occur in both directions (stronger and weaker). [23]

Bates' other source of evidence was the ability of some aphakics to accommodate. Firstly, these cases are exceptionally rare and therefore should be considered exceptions to the rule rather than the rule [4] and, secondly, evidence has been presented that there is no change in the refractive power of the eye in these cases. [24][25]

Critics of the Bates Method contend that if the cause of myopia is continuous tensing of the muscles, either ciliary or extraocular, the Bates Method theory is that it should be possible to cure (or noticeably improve) it by causing intentional relaxation of the muscles; a process most commonly done using injections or topical administration of atropine. The mainstream consensus on this, however, is that no significant improvement of the vision is obtained when muscles are relaxed in this manner. Although Bates claimed that the evidence against the orthodox theory of accommodation was "overwhelming", he acknowledged that the effect of atropine supported the orthodox theory in "about nine cases out of ten".[9][22]

Efficacy

Optometrists and ophthalmologists remain skeptical of Bates' theories and methods. Skeptic Martin Gardner characterizes Bates's book in Fads and Fallacies in the Name of Science, as "a fantastic compendium of wildly exaggerated case records, unwarranted inferences and anatomical ignorance." Bates theory of accommodation suggested the contraction of the ocular muscles resulted in changes in focusing power rather than changes in the lens and contraction of the lens zonules. Gardner argues that current high-resolution dynamic ultrasonic biomicroscopy has shown Bates' theory of accommodation (by elongation of the eyeball) to be false. Gardner suggested that the Bates method may seem to work, to a limited degree, by increasing the trainee's ability to interpret and extract information from blurred images.[19]

The purported benefits are generally anecdotal and medical research often shows no clinical benefit. The medical community is often critical of the Bates method due to a lack of evidence-based medical support.[22][26][27]

In the eighties and nineties, interest in biofeedback in turn stimulated some research into the Bates method. It was found in one study that myopes could improve their visual acuity with biofeedback training, but that this improvement was "instrument-specific" and did not generalise to other measures or situations. [28] In another study an "improvement" in visual acuity was found but the authors concluded that this could be a result of observers learning the task [29] Finally, in an evaluation of a training system designed to improve acuity, "no significant difference was found between the control and experimental subjects" [30] A 1997 review of this biofeedback research concluded that "controlled studies to validate such methods ... have been rare and contradictory." [31]

Safety

Avoidance of conventional treatment

Advocates believe the Bates Method to be safe. Critics concede that most of the Bates techniques are harmless, apart from the possibility that faith in the Bates system could deter people with eye conditions requiring prompt care from seeking conventional treatment. Professional Bates Method teachers use a disclaimer, which must be signed by the student, that emphasizes that a Bates Method teacher is not an Ophthalmologist.[32]

In humans the eye and brain development continues until approximately 8-10 years of age. For proper development of the visual pathways in the brain it is essential that clear images fall on the retina. Therefore it is very important that any refractive error is fully corrected in childhood in order to prevent the development of amblyopia.

Sunlight exposure

Bates gives several examples of patients' vision improving after having looked directly at the sun,[33] which in some situations may be dangerous. Figures in Chapter 17 of Bates' 'Perfect Sight Without Glasses' show several individuals looking at the Sun "without discomfort" and figure 48 shows somebody "Focussing the Rays of the Sun Upon the Eye of a Patient by Means of a Burning Glass" implying that this is a safe thing to do.[33] Regarding "sun-gazing" as beneficial he goes so far as to say that: "In some rare cases... complete cures have been effected by this means alone."[33] Regarding looking directly at the sun, Bates also remarks that:

"In my experience such light has never been permanently injurious. Persons with normal sight have been able to look at the sun for an indefinite length of time, even an hour or longer, without any discomfort or loss of vision. Immediately afterward they were able to read the Snellen test card with improved vision, their sight having become better than what is ordinarily considered normal."[33]

According to Thomas R. Quackenbush, Bates modified this suggestion after having written Perfect Sight Without Glasses by stating that the sun should only be allowed to shine on closed eyes.Cite error: The <ref> tag has too many names (see the help page).

Other methods

In recent years, the growing interest in alternative medicine has led to an increase in the popularity of the Bates Method and other methods claiming success in improving eyesight via visual training. One particularly controversial area is the efficacy of eye exercises in the treatment of myopia (near-sightedness) and whether the use of eyeglasses makes myopia progressively worse.

Several points of view exist about the use of eye exercises to treat vision problems:

  • Traditional mainstream ophthalmologists and optometrists use eye exercises to treat a limited range of problems, particularly problems involving muscular imbalances and problems with coordination of eye movement between the two eyes. (See orthoptics.)
  • Functional optometrists and optometric vision therapists are licensed, credentialed doctors of optometry, who specialize in treatment that involves eye exercises. They hold that such exercises are useful in improving a wide range of visual conditions, including focusing problems. The methods used are said to be backed by clinical studies and publications in peer-reviewed journals. (See vision therapy.)
  • The Bates method differs from systems that use eye exercises in a way that can be categorized as alternative medicine. Like homeopathic medicine, the treatments used and the explanations of how they are said to work are rejected by mainstream medicine[19], despite personal testimony[34] by people who claim to have been helped by such methods.

The See Clearly Method

The commercial See Clearly Method was shut down by a court order in November 2006. While it included a few elements of the Bates method, Bates practitioners are keen to distance themselves from it.[34]

Natural Vision Improvement

"Natural Vision Improvement" markets itself as a lifestyle method of improving eyesight by holistic means without the use of optical devices. It uses the Bates method "merged" with modern theories of brain function, character and responsibility for one’s self and state of being.[35] Various self-help books and programs exist claiming to improve vision "naturally" by various means.[36][37]

Steven M. Beresford agrees with Bates regarding the possibility of improving eyesight naturally, saying in his book : "Pretending that the traditional use of 'corrective' lenses is safe and effective is no longer acceptable. The public must be told the truth and given accurate information about the alternative methods of treatment now available." In the book, Beresford et al assert that corrective lenses are neither safe or effective and that vision can be improved without the use of glasses or contact lenses.[38]

See also

References

  1. ^ a b c William Bates. "Perfect Sight Without Glasses, Chapter 10".
  2. ^ http://www.central-fixation.com/bettereyesight.htm>
  3. ^ William Bates. "Perfect Sight Without Glasses, Chapter 19".
  4. ^ a b c d Marg, E. (1952). "[brain.berkeley.edu/pub/1952%20April%20Flashes%20of%20Clear%20Vision.pdf". Am J Opt Arch Am Ac Opt. 29 (4): 167–84. {{cite journal}}: Text ""Flashes" of clear vision and negative accommodation with reference to the Bates Method of visual training.]" ignored (help)
  5. ^ http://www.iblindness.org/books/bates/
  6. ^ http://www.effortlessvision.com/linksarticles.htm
  7. ^ Robyn E. Bradley (September 23, 2003). "ADVOCATES SEE ONLY BENEFITS FROM EYE EXERCISES" (PDF). The Boston Globe (MA).
  8. ^ Quackenbush, Thomas R. (2000). Better Eyesight The complete magazines of William H. Bates. North Atlantic Books. pp. page 643. ISBN 1-55643-351-4. {{cite book}}: |pages= has extra text (help)
  9. ^ a b William Bates. "Perfect Sight Without Glasses, Chapter 6".
  10. ^ William Bates. "Perfect Sight Without Glasses, Chapter 4".
  11. ^ William Bates. "Perfect Sight Without Glasses, Chapter 7".
  12. ^ a b c d e William Bates. "Perfect Sight Without Glasses, Chapter 9".
  13. ^ "Lifestyle causes myopia, not genes". 8th July 2004. {{cite web}}: Check date values in: |date= (help)
  14. ^ Jiang BC, Schatz S, Seger K. (2005). "Myopic progression and dark focus variation in optometric students during the first academic year". Clin Exp Optom. 88 (3): 153–9.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  15. ^ William Bates. "Perfect Sight Without Glasses, Chapter 8".
  16. ^ William Bates. "Perfect Sight Without Glasses, Chapter 24".
  17. ^ http://www.visioneducators.org/reducedlenses.htm
  18. ^ William Bates. "Perfect Sight Without Glasses, Chapter 12".
  19. ^ a b c Gardner, Martin (1957). Fads and Fallacies in the Name of Science. Reprint: Courier Dover. ISBN 0-486-20394-8.
  20. ^ http://www.central-fixation.com/batesmed/radicalcure.htm
  21. ^ Corbett's 'Help yourself to better sight'.
  22. ^ a b c Pollack P. The Truth about Eye Exercises. Philadelphia: Chilton Co., 1956, Chapter 3. available online
  23. ^ Preslan M, Cioffi G, Min Y. "Refractive error changes following strabismus surgery". J Pediatr Ophthalmol Strabismus. 29 (5): 300–4. PMID 1432517.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  24. ^ Bettman, J . W. (1950). "Apparent Accommodation in Aphakic Eyes". Amer. Jour. Ophthal. 33: 921–928.
  25. ^ Hirsch, Monroe J. (1950). "Apparent Accommodation in Aphakia". Amer. Jour. Optom. and Arch. Amer. Acad. Optom. 27: 412–414.
  26. ^ Kavale K, Mattson P.D. "One Jumped Off The Balance Beam": Meta-analysis of Perceptual-motor Training. Journal of Learning Disabilities 16:165-174, 1983.
  27. ^ Keogh BK and Pelland, M. Vision training revisited. Journal of Learning Disabilities 18:228-235, 1985.
  28. ^ Randle RJ (1988). "Responses of myopes to volitional control training of accommodation". Ophthalmic Physiol Opt. 8: 333–340.
  29. ^ Gallaway M, Pearls SM, Winkelstein AM; et al. (1987). "Biofeedback training of visual acuity and myopia: A pilot study". Am J Optom Physiol Opt. 64: 62–71. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  30. ^ Koslowe KC, Spierer A, Rosner M; et al. (1991). "Evaluation of accommotrac biofeedback training for myopia control". Optom Vis Sci. 68: 252–4. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  31. ^ G Rupolo, M Angi, E Sabbadin, S Caucci, E Pilotto, E Racano and C de Bertolini (1997). "Treating myopia with acoustic biofeedback: a prospective study on the evolution of visual acuity and psychological distress". Psychosomatic Medicine. 59 (3): 313–317.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  32. ^ Disclaimer http://www.visionsofjoy.org/disclaimer.htm
  33. ^ a b c d William Bates. "Perfect Sight Without Glasses, Chapter 17".
  34. ^ a b Visions of Joy. "Reaction to this court order by the natural vision improvement movement".
  35. ^ Janet Goodrich. Natural Vision Improvement. Greenhouse Publications, 1986. ISBN 0-89087-471-9
  36. ^ Online Books. Imagination Blindness.
  37. ^ Russell S. Worrall OD, Jacob Nevyas PhD, Stephen Barrett MD. "Eye-Related Quackery". Quackwatch. Retrieved 2007-02-12.{{cite web}}: CS1 maint: multiple names: authors list (link)
  38. ^ Steven M. Beresford, David W. Muris, Merril J. Allen, Francis A. Young. Improve Your Vision Without Glasses Or Contact Lenses : A New Program Of Therapeutic Eye Exercises page 7. Fireside, Inc; 1996. ISBN 0-684-81438-2.

Free online books and articles by Bates

Advocates of the Bates Method / Natural Vision Improvement