Clarifying the statment "over 70 percent myopic"

Discussion in 'Optometry Archives' started by otisbrown, Sep 30, 2005.

  1. otisbrown

    otisbrown Guest

    Subject: A High Percentage Myopia in School and College


    I previously stated that with certain groups of Eskimos, the
    percentage who were myopic increased to 85 percent.

    I do not have that report at this time -- however these
    statistics prove the same thing.

    One OD stated that this was not the case, but failed to
    present is "new" study.

    Here are some more recent statements of the percentage of
    school students whose refractive state moved from a positive value
    to a negative value (as a natural process). At least 70 percent
    and up to 85 percent at the higher levels.

    Here is the statement of those statistics.

    Are these statistics a "myth"? I guess that is
    the belief of the ODs on sci.med.vision. What do
    you think? Who is responsible? You or the OD?

    You asked that I "stick to the facts" concerning
    the dynamic behavior of then natural eye - so here
    are the facts. Do you deny them?



    +++++++++++++++++++++++++++++

    1) Lam and Yap (Lam, C.S. and Yap, M. "Ocular dimensions and
    refraction in Chinese Orientals", Proc. Int. Soc. Eye
    Res., 6:121, 1990) found that in a group of optometry
    students at The Hong Kong Polytechnic University, the
    prevalence of myopia was 75% in females and 69% in males.

    2) Goh and Lam (Goh, W.S. and Lam, C.S., "Changes in refractive
    trends and optical components of Hong Kong Chinese aged 19-39
    years," Ophthal. Physiol. Opt., 14:378-382, 1994) found
    that in 2000 first-year students at the University of Hong
    Kong, the prevalence of myopia was 87.5%.

    3) Lin et al (Lin, L.-K, Chen, C.J., Hung, P.T., and Ko, L.S.,
    "National- wide survey of myopia among schoolchildren in
    Taiwan, Acta Ophthalmol.", 185:29-33, 1988) found that in a
    national survey of children in Taiwan, the prevalence of
    myopia was over 70%.

    4) Lin et al (Lin, L.K., Shih, Y.F., Lee, Y.C., Hung, P.T., and
    Hou, P.K., " Changes in ocular refraction and its components
    among medical students - a 5-year longitudinal study", Optom.
    Vis. Sci., 73:495-498, 1996) found that in a study of 345
    National Taiwan University medical students, the myopia
    prevalence increased from 92.8% to 95.8%! over the five year
    period.


    ++++++++++++++++++++++++

    December 6, 2000

    By Liu Shao-hua
    Staff reporter
    Taipei Times

    Subject: Myopia Increases Among Children

    One of every five children in the first grade in Taiwan's
    elementary schools is myopic (nearsighted). The proportion of
    myopics in this group has increased from 12.1 percent in 1995 to
    20.4 percent this year, according to the results of a survey
    released by the Department of Health yesterday.

    The results also show that 60.7 percent of sixth graders in
    elementary schools, 80.7 percent of third graders in junior high
    schools, and 84.2 percent of third graders in senior high schools
    suffer from myopia. In addition, the number of seriously myopic
    children is also on the rise. The proportion of seriously myopic
    children among sixth graders in elementary schools has increased
    from 2 percent five years ago to 2.4 percent this year.

    Serious myopia is defined as exceeding 600 degrees (6
    diopters). Anything over 25 degrees (0.25 diopters) is myopia.
    Normal eyesight is zero degrees.

    "We appeal for reductions to children's work load in schools
    and the amelioration of visual environments in daily life," said
    Chen Tzay-jinn, director-general of the health promotion bureau,
    under the health department.

    The survey was conducted by the department, in cooperation
    with National Taiwan University and its hospital, and involved a
    sample of 12,000 students from four million students between the
    ages of 7 and 18 nationwide. Myopia has been on the increase in
    Taiwan ever since the first myopia survey in 1983. The department
    manages the survey every four or five years.

    The growth of nearsightedness among young children is thought
    to result from learning to read very young and using computers
    very young, Chen pointed out.

    Last year, the department and the Ministry of Education
    delivered official documents to kindergartens nationwide demanding
    that children not be taught to read or use computers too early.
    "But many teachers and parents protested against this appeal,"
    said the department officials. "They questioned exactly what they
    were permitted to teach if reading was not allowed."

    "We do hope that parents and teachers can heighten their
    awareness of myopia and understand that early learning does not
    guarantee students' performance in the future, but it does bear a
    strong correlation to defects in vision," Chen said. The
    department also appealed for children under the age of 10 not to
    be taught how to use computers.

    Senior high school students suffer the highest rates of
    nearsightedness, at over 84 percent. "It reached a plateau five
    years ago and has not changed this year. But their myopia has
    become more serious," Chen said. According to the survey, 20
    percent of third graders in senior high schools are seriously
    nearsighted.

    Many people thought operations could cure myopia. "But the
    superficial improvement of vision does not better the health of
    the eye. More importantly, it might reduce people's awareness of
    other problems associated with nearsightedness, apart from visual
    ones," said Lin Lung-kuang, ophthalmology professor at National
    Taiwan University. "Myopia cannot be cured. We have to prevent
    children from becoming nearsighted. Don't let them use their
    vision too early," Lin urged.

    Because of the public's lack of awareness of myopia, the
    department estimated its prevalence would continue to grow.
    "Singapore resembles Taiwan in many respects and the extent of its
    myopia problem might serve as a warning for us," Chen said.


    ++++++++++++++++++++++++++++++++

    Subject: Rejection of the plus for prevention.


    Clearly this is a "Mexican stand-off" on the use of the
    plus-for-prevention. (It is about time that the preventive method
    be "suggested" -- even with the "understood" resistance to using
    it "correctly".

    It is up to the person concerned with true-prevention to
    learn to use it "effectively." How much does the person understand
    of this issues, and how much does he value his distant vision?

    I would suggest that prevention is a "now or never" choice,
    where the minus lens is much easier and obvious -- but is creating
    "stair-case" myopia as a "secondary consequence" of the desire to
    make distant vision very sharp with an excessively strong minus
    lens.

    But what is "obvious" is not necessarily the "right" or
    better solution.

    Best,

    Otis
     
    otisbrown, Sep 30, 2005
    #1
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  2. otisbrown

    drfrank21 Guest


    The following (see below) is a brand new study just published
    in Australia which I'm sure Otis will use his "Otis-speak"
    (garbage in, garbage out)to hem and haw this very valid study.

    frank


    Little evidence for an epidemic of myopia in Australian primary school
    children over the last 30 years

    Barbara M Junghans1 and Sheila G Crewther2
    1School of Optometry and Vision Science, University of New South Wales,
    Sydney, UNSW Sydney 2052. Australia
    2School of Psychological Science, La Trobe University, Bundoora 3083,
    Australia

    BMC Ophthalmology 2005, 5:1 doi:10.1186/1471-2415-5-1

    This is an Open Access article distributed under the terms of the
    Creative Commons Attribution License
    (http://creativecommons.org/licenses/by/2.0), which permits
    unrestricted use, distribution, and reproduction in any medium,
    provided the original work is properly cited.

    Recently reported prevalences of myopia in primary school children vary
    greatly in different regions of the world. This study aimed to estimate
    the prevalence of refractive errors in an unselected urban population
    of young primary school children in eastern Sydney, Australia, between
    1998 and 2004, for comparison with our previously published data
    gathered using the same protocols and other Australian studies over the
    last 30 years.

    Methods

    Right eye refractive data from non-cycloplegic retinoscopy was analysed
    for 1,936 children aged 4 to 12 years who underwent a full eye
    examination whilst on a vision science excursion to the Vision
    Education Centre Clinic at the University of New South Wales. Myopia
    was defined as spherical equivalents equal to or less than -0.50 D, and
    hyperopia as spherical equivalents greater than +0.50 D.

    Results

    The mean spherical equivalent decreased significantly (p < 0.0001) with
    age from +0.73 ± 0.1D (SE) at age 4 to +0.21 ± 0.11D at age 12 years.
    The proportion of children across all ages with myopia of -0.50D or
    more was 8.4%, ranging from 2.3% of 4 year olds to 14.7% of 12 year
    olds. Hyperopia greater than +0.50D was present in 38.4%. A 3-way ANOVA
    for cohort, age and gender of both the current and our previous data
    showed a significant main effect for age (p < 0.0001) but not for
    cohort (p = 0.134) or gender (p = 0.61).

    Conclusions

    Comparison of our new data with our early 1990s data and that from
    studies of over 8,000 Australian non-clinical rural and urban children
    in the 1970's and 1980's provided no evidence for the rapidly
    increasing prevalence of myopia described elsewhere in the world. In
    fact, the prevalence of myopia in Australian children continues to be
    significantly lower than that reported in Asia and North America
    despite changing demographics. This raises the issue of whether these
    results are a reflection of Australia's stable educational system and
    lifestyle over the last 30 years.


    The prevalence of myopia is currently receiving worldwide attention as
    many recent studies report dramatic increases over the last 20 years
    [1,2]. Myopia and its aetiology is an interesting example of the
    intertwining of 'nature and nurture' with both genetics and life-style
    environment as important issues [3]. There is strong evidence
    indicating that genetic inheritance is a major contributor, both from
    the examination of prevalences across different racial backgrounds [4],
    from family pedigrees [5] and from twin studies [6]. However, there is
    increasing evidence suggesting that high heritability does not preclude
    rapid environmentally-induced increases in prevalence [7], rather,
    inherited factors are likely to both drive the susceptibility and
    resistance to environmentally-induced myopia [6,8].

    Despite much research interest over the last half century, there have
    been surprisingly few well-designed epidemiological studies of
    refractive error with large numbers of randomly selected younger school
    children to form the basis of valid world wide comparisons of the
    earliest stages of development of myopia [3,9,10]. However, a group
    sponsored by the World Health Organisation in 2001 has devised a
    protocol to be used during studies of refractive error across different
    cultural and ethnic settings: the 'Refractive Error Study in Children'
    (RESC) [11].

    In general, estimates of the prevalence of myopia have shown less
    increase in the Western world than in Asia, and less increase in rural
    than in urban populations [1,10,12-16]. Five very large studies across
    two decades and involving over 10,000 children in Taiwan are very
    important for understanding the changing prevalence of myopia in young
    Asian children (1.8% in 1986 rising to 12% in 1995 for 6 year olds, 40%
    rising to 56% for 12 year olds) [2]. A similar change is also reflected
    in Singaporean studies of myopia in military conscripts aged 17 years
    (26% to 83% from the late 1970s to the late 1990s as reviewed by [1]),
    of whom notably 82% were Chinese [17].

    It has often been suggested that myopia is more prevalent in ethnic
    Chinese (reviewed [18]), but only relatively recent studies compare the
    prevalence of myopia in young ethnic Chinese children living either in
    China and in other countries [1,12,15,18-22]. For younger Chinese
    children aged around 5-7 years, the prevalence of myopia was found to
    range from under 5% in rural China [14,23] to 24% in Chinese Malays
    [20] and 30% in urban Hong Kong [19,22]. For older Chinese children
    aged 11-12 years, the prevalence ranged from 23% of rural
    Chinese[14,23] to 40% in urban China[12], 47% of Chinese Malays [20]
    and 57% in urban Hong Kong [22]. Japan has a similarly high prevalence
    of myopia in young school children estimated in recent times to be
    43.5% of 12 year olds [24].

    By comparison, the epidemiology of refractive error for young
    Australian school children is relatively well documented and presents a
    very different profile. A number of studies were carried out in the
    early 1970s and the 1980s on relatively large groups of unselected
    primary school children from the socio-economic extremes (generally
    aged 5 to 12 years), and indicated a prevalence of myopia ranging from
    approximately 3% to 13% (see Table 1) [25-29]. Two of those early
    studies investigated children largely from underprivileged, rural,
    families [26,27], and the other was of children from several, middle to
    upper socio-economic class private schools [25]. One smaller study was
    carried out in the mid 1980s on children from a representative
    selection of government schools in Brisbane [29], and would therefore
    have investigated children from a broader range of backgrounds.
    Interestingly, this latter study was the only Australian study to have
    determined refractive error under cycloplegia, yet yielded the highest
    prevalence of myopia. Thus, it has been difficult to determine whether
    the prevalence of myopia has increased in young school children in
    Australia as reported elsewhere. The majority of Australian residents
    are of Caucasian extraction living a very western lifestyle, leading
    one to expect the prevalence of myopia to be similar to that found in
    US or Europe. Yet, studies suggest that the prevalence of myopia in
    Australian primary school children is low by world standards [10].

    In 2003 we reported the relative proportions of refractive errors in a
    large unselected primary school population of 2,535 children drawn from
    a very broad range of socio-economic backgrounds in Sydney, the largest
    city in Australia, in the early 1990s [30]. The children attended
    fourteen primary schools and two preschools. As in the earlier studies,
    the proportion of children with myopia greater than -0.50 DS spherical
    equivalence, as determined by non-cycloplegic retinoscopy, was found to
    be low by world standards (1.0% of 4 year olds rising to 8.3% of 12
    year olds). We have now analysed the prevalence of refractive error in
    a new similar group of 1,936 children unselected primary school
    children drawn generally from the same area as our first study.

    The study design is a retrospective examination of records of the
    Vision Education Centre (VEC) [31] school vision screenings (so named
    because parents were not present to ratify history) conducted in the
    Clinic of the School of Optometry and Vision Science, UNSW. Approvals
    for the study and permission to approach schools were obtained from the
    Committee for Use of Humans in Research at the University of New South
    Wales (UNSW), Sydney, Australia. The protocols adhered to the tenets of
    the Declaration of Helsinki. Parents or guardians were provided with an
    information sheet and requested an outline of known symptoms. Signed
    consent was required prior to a child's participation.

    Sampling and recruitment

    Permission was obtained from the NSW Department of Education and the
    NSW Catholic Education Office to approach all schools in the eastern
    region of Sydney (some thirty coeducational primary schools) to send
    entire classes to the VEC. A flyer was sent describing the VEC science
    excursion and age-appropriate eye examination, inviting Years 1, 3 and
    5 particularly to participate.

    The group of 1,936 children examined came from the eastern suburbs
    along the southern beaches of Sydney, and may be thought of as randomly
    selected with little likelihood of bias to the data as individual
    classes were free to respond. Children were drawn from twelve
    government and non-government primary schools and one pre-school and
    attended the clinic only once. During the 1996 Australian Bureau of
    Statistics census 14,785 children aged 4 to 12 years were recorded in
    this region (Randwick and Waverley precincts of Eastern Sydney) who
    came from a very broad range of ethnic and socio-economic backgrounds
    present, where 37 different languages might be spoken in the home [32].
    This was reflected in the children attending VEC. Census data indicate
    approximately 9% of the children in the current study were likely to be
    of Asian origin [32], a figure supported by our interpretation of
    family name for each child [30]. Participation in the eye examinations
    was typically well over 90% for each class, with teachers reporting
    non-participation to be predominantly due to illness on the day. Less
    than 3% of parents intentionally prevented participation, even if eye
    care had previously been sought. This particularly high participation
    rate was largely due to the attraction of a an age-appropriate
    student-centred hands-on science lesson about eyes and vision [31]
    delivered alongside the eye examination.

    Clinical examination

    The comprehensive optometric examination by experienced paediatric
    practitioners included all age-appropriate tests meeting Australian
    Optometric Competency Standards, except that parents/guardians were not
    present to ratify history. Refractive error was determined by
    non-cycloplegic retinoscopy with optical fogging while the child
    maintained fixation on a distant non-accommodative (6 metre) target. In
    most cases refractive status was confirmed by subjective refraction.
    Other tests included letter visual acuity at 6 m and 33 cm, cover test
    for strabismus, motilities, saccades, pupil reactions, near point of
    convergence, heterophoria, stereopsis, accommodative facility, colour
    vision and ophthalmoscopy.

    Justification of choice of testing procedures

    Cycloplegic retinoscopy was not undertaken for many reasons including
    the fact that VEC studies started prior to the 2000 convention
    suggesting use of cycloplegic retinoscopy for studies of refractive
    error prevalence [11]. Secondly, the VEC visit was meant as an
    excursion and the children had to return to normal classes with near
    work demands after the morning outing. Thirdly, it was important for
    comparison purposes to use refractive data procured under the same
    conditions as that used for the earlier groups of children. Fourthly,
    an initial evaluation without cycloplegia is necessary in order to
    understand daily function. Fifthly, non-cycloplegic retinoscopy was
    only one component of the exam. Outcomes regarding a decision to refer
    would not alter for most children had a cycloplegic refraction been
    carried out, as several other near function tests that would also
    indicate the possible existence of latent hyperopia or pseudo-myopia
    were included. Lastly, the degree of refractive error may in fact be
    influenced by cycloplegia (see Discussion for elaboration [33-38]).

    Autorefractors were not employed as hand-held versions were unavailable
    when the first cohort was seen. Equally as important, there is no
    convincing evidence that the proportion of myopes identified in the
    sample would have changed [39].

    Comparison with earlier data

    To compare the estimated prevalence of myopia in this urban population
    of 'Australian children' over the last decade, this more recent 2000s
    data set was analysed against data from an earlier cohort of 2,322
    children with similar demographics seen in the early 1990's, using the
    same testing protocols and seen at the same venue [30]. The optometric
    results of that earlier cohort have previously been reported [40], and
    it was noted that 7.1% of those children were already wearing
    spectacles [30], indicating that our recruitment procedure did not
    preclude children already under the care elsewhere. The data for any
    child examined in both cohorts was deleted from the earlier data set to
    avoid bias in the analysis. The mean date of assessment for this last
    2000s cohort was September 2000, and for the early 1990s cohort was
    June 1992. Thus, the average gap between assessments of children from
    the two cohorts was 8 years and 3 months.

    Statistical analyses

    Data was analysed by Analysis of Variance ANOVA (StatView software).
    Only refractive data from right eyes was used for the current
    refractive class analysis, as the correlation between right and left
    eye refractions was extremely high (p < 0.0005). The preferred
    criterion to define myopia in this study is that used clinically in
    Australia: a spherical equivalent equal to or more minus than -0.50 D.
    However, as myopia more minus than -0.50 D has occasionally been used
    to define myopia in epidemiological studies [13,19,41], analyses using
    the criterion 'myopia more minus than -0.50 D' were also performed for
    comparison. Hyperopia was defined as spherical equivalents greater than
    +0.50 D. Thus, emmetropia for this study was defined as refractions in
    the range -0.25 to +0.50 dioptres spherical equivalence inclusive.
    Means are quoted with the associated standard error.


    Outline Results
    The records of 1,936 children aged 4 to 12 years from a non-clinical
    unselected population examined during the six years from March 1998 to
    May 2004 were analysed retrospectively to estimate the prevalence of
    different types of refractive error. Primary schools of their own
    choice sent more children from years 1, 3, and 5, which resulted in
    unequal numbers of children in each of the age groups. There were 925
    boys and 951 girls, and the relative numbers for both males and females
    in each age group are shown in Table 2. For 59 children, the gender was
    not indicated on the record card and could not be inferred with
    certainty from the given name. The data not associated with gender has
    only been included in analyses entitled 'All' as shown in Tables 2 and
    3. Mean age was 8.36 years. The relative proportions of the different
    classifications of refractive error for all children combined
    (including those of unknown gender) for each age group are shown in
    Table 2.

    The mean spherical equivalent refraction of all 1,936 children was
    +0.45 ± 0.02 DS, however it should be noted that there is a
    preponderance of children aged 5-6, 9 and 11 years old corresponding
    with Years 1, 3, and 5 of primary school. Overall, there was no
    significant difference in spherical equivalent refractive error between
    girls and boys (p = 0.697). In general, mean refraction demonstrates a
    highly significant shift towards less hyperopia with increasing age (p
    < 0.0001) from 0.73 ± 0.1DS for 4 year olds to 0.21 ± 0.11 for 12
    year olds, however this is more noticeable after the age of 9 years as
    seen in Fig. 1. With increasing age, more children are found in the
    emmetropic category and fewer in the low hypermetropic category.

    A summary of the relative proportions of myopia and hyperopia for this
    cohort of children of all ages seen during the six years ('2000s' data)
    is given in Table 3. The majority of children screened are emmetropic
    by our criteria: 53.0% averaged across all ages. The proportion of
    children manifesting moderate to high degrees of hypermetropia
    (=+1.50 DS) is 6.2% across all ages. Only 6.9% of children of all
    ages had refractive errors more minus than -0.50 DS, ranging from 2.3%
    of 4 year olds to 13.3% of 12 year olds (Fig. 2). If the more liberal
    definition of myopia is applied (myopia equal to or more minus than
    -0.50), then 8.4% of all children were myopic (ranging from 2.3% of 2
    year olds to 14.7% of 12 year olds). Only 0.8% of the 1,936 children
    were more than -4.00 DS myopic.


    An analysis of the prevalence of refractive errors in young school
    children in eastern Sydney during the last thirteen years has been
    presented. The latest data gathered from 1,936 unselected primary
    school-aged children in the last 6 years, indicates that the prevalence
    of myopia remains quite low compared to that reported for the western
    world and Asia, especially as refractive error was established by
    non-cycloplegic retinoscopy (as will be discussed later). These
    findings are not significantly different (p = 0.13) to our previous
    report [30] indicating that 6.5% of 2,535 unselected children aged 4 to
    12 years seen in the early 1990s were myopic by at least 0.50 D.
    Notably, those children were of similar socio-economic and ethnic
    status drawn from the same region of Sydney and seen at the same Centre
    using the same testing protocol.

    Therefore, if we take the total 4,258 children seen since 1990, the
    relative frequency of refractive error across all is: 54.2% emmetropic
    by our criteria, 32.3% low to moderate hyperopes, 5.3% myopic greater
    than -0.50D spherical equivalence and 7.4% myopic by at least -0.50 DS.
    The number with myopia of at least -4.00 DS was an extremely small
    0.6%.

    The prevalence of myopia in Sydney primary school children compared to
    the rest of the world

    As alluded to in the introduction, the proportion of Sydney children
    with myopia is dramatically less than in Asia. Indeed, the proportion
    appears significantly lower than in the USA [41] and Canada [42] (4%
    and 6% of 6 year olds respectively, or 20% of 12 year olds in USA), but
    higher than urban India with only 4.4% of all school children under 16
    years myopic [13] and higher particularly than in other less developed
    countries [10].

    In the past, a lack of internationally accepted definitions for
    'myopia' has hampered valid comparisons across the various studies
    [10]. Commonly the criteria 'greater than -0.50 DS' or 'at least -0.50
    DS' are employed. However, our separate analyses using both of these
    criteria only resulted in a difference of 1.5% of all children included
    as myopic, in keeping with other dual analyses [13,41], and is low
    either way when compared with Asia or North America.

    Comparison across studies is also difficult when only an 'overall' mean
    refraction is presented covering all children in a study, due to the
    well known increasing prevalence of myopia with age. Indeed, the
    comparison of data from our own two data sets is confounded to some
    extent by the slightly different age profiles for each cohort. However,
    in neither cohort was the age range nor mean significantly different,
    so the similar proportion of myopes is not unexpected.

    Comparison of refractive error with and without a cycloplegic agent

    The question of optimal ocular conditions for comparison of the
    prevalence of refractive errors remains controversial. A cycloplegic
    agent is typically proposed as the gold standard [3,43,44] in the
    belief that it will eliminate ciliary muscle action or spasm, and thus
    unmask latent hyperopia or pseudomyopia. Thus, the use of a cycloplegic
    would be firstly predicted to lead to a decrease in the prevalence of
    myopia, and an increase in the prevalence of hyperopia. However, as a
    cycloplegic also leads to associated mydriasis and the introduction of
    unpredictable spherical aberrations, it is arguable that cycloplegia
    will induce unpredictable errors. In fact, Gao et al [38] in 2002
    reported significant changes in the refractive components of children's
    eyes under conditions of deep cycloplegia and mydriasis that were
    greatest in hyperopic eyes and smallest in myopic eyes, adding no
    definitive evidence as to the relative efficacy of cycloplegia.

    Thus there appears to be no scientific concurrence regarding the
    efficacy of cycloplegia for studies on the prevalence of myopia
    [35-37], with several major studies electing to use cycloplegia (see
    review in [10,9,11]) and others not [18-21,23,42,45]. Presumably this
    design variability exists because there is no decisive evidence
    indicating a difference between refractions determined with and without
    a cycloplegic agent in eyes that have a myopic refraction. In general,
    a more positive retinoscopic finding is reported under cycloplegia,
    though considerable individual variation is seen including a myopic
    shift in some [33,35-37,46]. Not surprisingly, the differences noted
    decreased both with age and with less positive refraction.

    As our refractive data was derived from non-cycloplegic retinoscopy we
    readily concede that mean refractive error may be less hyperopic than
    if a cycloplegic had been used. However, we suggest that as the
    influence of a cycloplegic is uncertain and is of least concern for
    myopes, the estimated prevalence of myopia will not be significantly
    altered by our decision to not use a cycloplegic. In support of this
    notion are new conference data from Rose et al [47,48] reporting
    refractive status ascertained by cycloplegic autorefraction in over
    1,000 children aged 6-7 years from across the same city of Sydney.
    They reported values of 'around 3%' for the prevalence of myopia of at
    least 0.50D [47], and then the value of 1.5% for myopia of
    'approximately 0.50D' [48] with a participation rate between 73 and
    80%. From Table 2 it can be seen that 2.4% of our 6 year olds in the
    current study were at least 0.50D myopic - a value that is strikingly
    similar.

    Demographics versus lifestyle

    Worldwide patterns of the prevalence of myopia suggest significant
    differences are likely to be due to the different demographics and
    lifestyles [1,10,49]. Zadnik [41] concedes that the increase in numbers
    of myopic children in the US Orinda study may be due to changing ethnic
    demographics. The apparent slight increase in myopia in Australia
    reported in the current study may also be in part accounted for by our
    changing ethnic demographics in urban areas. However demographics and
    ethnic compositions are unlikely to be responsible for the large
    changes reported in Asian and some other western countries [1,50].

    Whatever way it is argued, our results indicate little evidence for an
    epidemic of myopia although there is a developmental trend towards an
    earlier decrease in hyperopia to the point of myopia. Thus, the
    question of whether it is a matter of lifestyle, or perhaps familial
    environmental stress, or more, remains. Certainly, the education system
    and housing has changed little in Australia the last 30 years. By
    comparison, most Asian children participating in myopia epidemiological
    studies reportedly are more likely to live in high-rise residential
    blocks [17] and have strong demands at school to memorize along with
    parental and peer pressure to do well, and for some, a competitive
    entrance examination to enter school [19,51].
    Conclusions
    It is concluded that despite some differences in methodology across
    earlier studies, the prevalence of myopia in young Australian school
    children does not appear to have increased significantly over the last
    30 years if one allows for the change in ethnic demographics. It is
    also proposed that an explanation for the large increase in prevalence
    of myopia reported in other countries must include questions relating
    to lifestyle in addition to genetic propensity.
     
    drfrank21, Sep 30, 2005
    #2
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  3. otisbrown

    aaaJoe Guest

    Oits - this was a great post. Well done! It sure raises some
    interesting and very important questions. Maybe children
    are not meant to do a lot of close work so early in life. At
    least not for extended periods. The parents were lamenting
    the lack of learning in the children if they weren't reading.
    Maybe the parents are the ones that should be teaching them.
    Then that wouldn't entail extended close work.

    Just a thought.

    Subject: A High Percentage Myopia in School and College
     
    aaaJoe, Oct 1, 2005
    #3
  4. otisbrown

    aaaJoe Guest

    Chinese parents have the highest respect for education and will start the
    learning process as early as possible. If Australians aren't so myopic
    that means that Australian kids aren't doing so much close work. And
    their scholastic scores would solidify that point. In a music school
    I used to attend the Chinese parents (the population of the city was about
    1/4 Chinese yet 90% of the students were Chinese - and it was NOT a Chinese
    music school!) would register their children BEFORE they were born.
    Because there was a 2 year waiting list and they wanted to have them
    started at age 2. Myopia is always the highest where the children
    start close work the earliest and do it the most. That's why urban
    kids are more myopic (higher scholastic standards and competition)
    then rural kids.
     
    aaaJoe, Oct 1, 2005
    #4
  5. otisbrown

    otisbrown Guest

    Dear Joe (GG),

    These ODs like to pull out ONE study that they love -- while
    totallly ignoring the 70 percent to 80 percent that has
    developed for the Chinese. Says a lot about their
    selective and blind bias. But you make your own
    judgment.

    I was well award that SOME children have a "bad habit".
    Particularly when taught to read at a very young age.
    They "pull" the book in close about 4 inches (i.e., -10 diopters,
    where "distance" is zero diopters).

    The parents think this is "cute" -- so they ENCOURAGE the
    child to CONTINUE doing this. Naturally, the ODs keep
    their mouth shut -- because they can not admit
    the proven effect this has on that NATURAL primate eye.
    (That would be "bad for business" -- even though
    it is now scientific truth.) But ever so -- if the
    OD even SUGGESTED that doing that was a "problem"
    the parents will totally ignore this "warning". They
    want there child to "compete" in academics -- even
    if the poor kid gets stair-case myopia a part
    of the "price" to be "smart".

    So each group "passes the buck" and thinks
    some one else is responsible. The ODs are
    "protecting" their "position". (Why should they
    put themselves "at risk" for your long-term visual
    welfare -- when YOU will not take it seriously?

    The net result is "galloping" myopia -- and every one
    says "gee wiz -- some one should do something".

    I think that we all should do more "thinking" about
    these issues -- but then when I suggest that your
    own intellect is involved I get these "warniings" from
    you-know-who.

    Best,

    Otis
     
    otisbrown, Oct 1, 2005
    #5
  6. otisbrown

    Dr. Leukoma Guest

    Can you say
    Oakley-Young-Oakley-Young-Oakley-YoungOakleyYoungoakleyoungoakelyoung...


    DrG
     
    Dr. Leukoma, Oct 1, 2005
    #6
  7. otisbrown

    otisbrown Guest

    Dear DrG,

    Can you say -- continue the traditional minus lens with
    out ANY CHAGE for the last 400 years.

    Can you say IGNORE ALL SCIENTIFIC PROOF YOU DON'T LIKE.

    Can you say "stair-case myopia is not my responsibility".

    That is always the "fault" of the person's "bad heredity", thus
    avoiding ANY responsibility for anything?

    But, thank to the compassionate and reasonable Jacob
    Raphaelson I have learned about this "office-myopia" -- and
    how to avoid it.

    I regret that kind of "blindness" but you are making
    it a "scientific fact". This is very similar to
    "bleeding" people to "solve" medical problems.

    But it is true that the minus does give an "instant" solution.
    That is about the only difference.

    But do not take this a "critical". You simply state the
    "majority opinion". For the readers, there is a
    "second opinion", that does not reflect this
    kind of arrogance. It is nice that DrG has
    made this issue clear to you.

    Enjoy,

    Otis
     
    otisbrown, Oct 1, 2005
    #7
  8. otisbrown

    Dr. Leukoma Guest

    Plus lenses have been around longer. If they cured myopia, then there
    wouldn't be any. Get it? Even a society of chimpanzees would have
    figured it out by now.
    You can't even search PubMed for a study on Eskimo myopia, so don't
    lecture me.
    Hmmm. Can you say hocus pocus maybe these plus lenses will help you
    focus?
    I don't see you promoting anything remotely resembling responsible
    advice. You just keep carping about how your high myopia ruined your
    career as a pilot.
    Then, show us the scientific studies that show how your recipe
    successfully prevented myopia in a group of subject. In fact, at this
    point I would be happy just to see a list of people who were going to
    get myopia but didn't thanks to you.
    I'm open to being convinced. You just haven't presented any
    justification.
    Minus does give vision to a nearsighted person. What is the right
    amount of time to make a 3 diopter myope wait to be able to obtain a
    driver's license? What is so humane about preventing a child from
    excelling in sports because of a visual handicap? The world is not
    going to wait for you to present your Magnum Opus, Otis.
    There are many opinions. Not all of them work as claimed.

    DrG
     
    Dr. Leukoma, Oct 1, 2005
    #8
  9. otisbrown

    LarryDoc Guest

    What's with all the quoting? A stuck key on your keyboard or something?
    You are defining yourself. Good! You're finally getting "it".
    Yeah, because it exists only in your mind.
    Who said that?
    Cool! Another "Otis term" .
    Blindness means "no vision", not blurry vision you idiot. And for your
    information, bloodletting has some scientific merit, especially when
    using leaches. Your theory, on the other hand, does not exist in the
    world of scientific reality, yet you continue to preach it like some
    sort of crazed zealot.
    "Your" second opinion reflects either your ignorance or lunacy. I don't
    think you have enough intelligence to be arrogant.

    Otis, old man, you are, every day, digging yourself deeper and deeper
    into a pit from which you will sooner or later disappear. Why not just
    get it over with. Inquiring minds are getting tired of waiting for to
    "self-destruct."
     
    LarryDoc, Oct 1, 2005
    #9
  10. otisbrown

    otisbrown Guest

    Dear Mike,

    Subject: You obviously have no clue what we recommend. -MT

    Then why not make the recommendations here and now.

    Let us say you have a child whose parents checked
    his vision at 20/40 (at home).

    In a darkened room you have him read a Snellen, and
    find that it takes about a -1.5 diopter lens to "clear" the
    20/20 line. William Stacy knows that the retina's of
    some children have the capablity of resolving 20/10
    letters. So you continue to increase the strength
    of that minus lens until the 20/10 line is cleared.
    That takes a -2.0 diopter lens.

    Now, the child is going to be impressed with how
    sharp you have made his vision.

    What do you tell the parents:

    1. Do not wear that minus lens -- unless absolutly
    necessary. Take it off at all other times.

    2. Wear that -2 diopter lens ALL THE TIME.

    What do you recommend?

    Best,

    Otis
     
    otisbrown, Oct 1, 2005
    #10
  11. otisbrown

    Dr. Leukoma Guest

    The state-of-affairs you have depicted is not within the realm of
    reality, so there is no point in commenting.

    DrG
     
    Dr. Leukoma, Oct 1, 2005
    #11
  12. otisbrown

    drfrank21 Guest

    You're missing the boat. This Australian study, along with others,
    shows that there is not an universal increase in myopia (especially
    the 70% stat) and that one needs to consider the genetic propensity
    as well.

    It would be interesting for someone like you or Otis to actually
    spend a few days observing in an optometric clinic/practice to
    realize that it's not all cut and dried like Otis believes. Then
    you could see the countless number of individuals who do NOT
    progress or change their myopic posture while wearing their full
    correction or others that do increase even after they broke or
    lost their most recent pair of glasses and were wearing an older
    pair. Or the student that was wearing her sister's glasses (who
    was more minus than herself)and did not increase her refractive error.

    But Otis would simply pretend that there was a conspiracy or that
    the O.D.'s were somehow incompetent.

    frank
     
    drfrank21, Oct 1, 2005
    #12
  13. otisbrown

    Dr. Leukoma Guest

    What indeed would motivate Otis to do this?

    He is seemingly conducting a one-man army against optometrists for some
    reason. I wonder if he is looking for a scapegoat for his own genetic
    myopic background?

    DrG
     
    Dr. Leukoma, Oct 2, 2005
    #13
  14. otisbrown

    otisbrown Guest

    Dear DrG,

    Otis> The reason -- the person's right to choose between
    the "traditional minus lens" and the preventive plus -- when it
    makes sense to do so.

    Otis> The science of the natural eye's behavior.

    Otis> I goal of helping my sister's children make a choice
    in the matter -- even though prevention-with-plus is honestly
    difficult.

    Otis> To recognize that some people have the motivation
    to do this work correctly, even facing these difficulties.

    Otis> An finally, to assist my niece and nephews recognize
    some "bad habits" in there own children that are condusive
    to producing a situation where the natural eye will change its
    refractive state from a positive value to a negative value -- when
    placed
    in a confined environment. This makes the first "line of defense"
    the parents -- and the monitoring of those "bad habits" a personal
    or parental responsibility.

    DrG> What indeed would motivate Otis to do this?

    Otis> My desire to help them understand the imperative
    nature of prevention -- as an either-or choice on the
    threshold. To undrestand the over-prescription policy
    of the "majority opinion" and the direct consequence of
    that policy. To transfer "control" of this issue to the
    parent. To recognize that this isssue is one of accurate
    preception of the natural eye's behavior, and that
    the implementation is "low cost" if under control of
    the parents. But it is indeed a motivational issue
    for the parent and child. That means that they will
    be making this judgment -- and not you.


    DrG> He is seemingly conducting a one-man army against optometrists
    for some
    reason.

    Otis> Absolutly false. I support Steve Leung OD and
    all other optometrists who will offer the plublic an
    honest discussion of these issues. You do not
    judge that you have this "professional responsibility",
    and that you can "commit" a person to the full-time
    wearing of a minus lens without that discussion.
    Steve Leung judgest (and respects) the person concerned
    with this issue. I SUPPORT ALL OD WHO RESPECT
    A PERSON IN THIS MANNER. That is NOT
    an attack on "all ODs". Only the arrogance
    of the "majority opinion".



    DrG> I wonder if he is looking for a scapegoat for his own genetic
    myopic background?

    Otis> What I do respect it the design and behavior of the
    fundamental eye -- as a system that controls its
    refractive state to its average-visual environment. This
    has been proven many times with primates and other
    animals. Such testing is prohibited on humans -- but
    you can draw the correct conclusion by studing
    (by analysis) the actual behavior of the eye in this manner.

    Otis> I did have some "poor" reading habits as a young
    child. I remember them well -- and I regret them. Given
    my knowledge of the eye's proven behavior -- I would not
    do them a second time. But life is a one-way street -- and
    we do not get a "second chance" at this. For this
    reason I have made this "situation" clear to my
    sister's chidren, so that they understand that they
    can insist that there children not engage in these
    visual bad-habits. Thus true-prevention must start
    at home -- with the family. It is certain that you have
    no control over this -- only the parents and child.

    Otis> If their children are 20/20 (refractive state zero to
    +1.5 diopters) at age 5, it is almost certain that they
    can keep their refractive status positive -- by correct
    use of the plus -- when necessary.

    Otis> Thus the real issue will be the extent that they
    are willing to help there own children understand these
    issues -- and take responsible actions to prevent
    the develpment of a negative refractive state (at a
    natural process) for them. If they do this successfully
    (always pass all visual acuity requirments) then you
    will not be "prescribing" a minus lens for them.

    Otis> I obviously have no control over what actually
    will develope -- so the actions they take will be up to
    them.

    Otis> In other words, a "fighting chance" is better
    than no chance at all. The Oakley-Young study
    is VERY CLEAR on that point. It is time to
    learn from the mistakes of the past -- and
    not keep repeating them.

    Best,

    Otis

    DrG
     
    otisbrown, Oct 2, 2005
    #14
  15. otisbrown

    Dr. Leukoma Guest

    I agree that your sister should not be placing her children in a closet
    and keep them there. Is that what she does?
    First of all, the parents are always "in control" of the issue. To
    think otherwise is completely delusional.

    What part of the eye's natural behavior do you use to frighten people?
    Do you mean the part about putting young primates into very high minus
    lenses? The real world correlate to that would be if a mother brought
    her child into my office, and despite the fact that the child was 20/20
    and had zero refractive error, I place the child into 10 diopter minus
    lenses.
    Yes, I see that you support Steven Leung. How many referrals to you
    send him, or cause to be sent to him based upon that website of yours?
    I rest my case. In this pile of blather, there is no mention of the
    genetic basis for myopia.
    OK, you are busted on that statement. You went way over the top on
    that one. You should stick to pilots.
    The real issue will be the extent that they believe your previous
    statement about the certainty of prevention with a plus lens on a five
    year/old.
    Sure you have control, because you cleverly wrap your advice in the
    cloak of authority.
    The Oakley-Young study was very clear that myopes with nearpoint
    esophoria will show less mypopic progression if they wear bifocals. It
    says nothing about preventing myopia in a five year/old by wearing plus
    lenses. You go way beyong the conclusions of that study.

    DrG
     
    Dr. Leukoma, Oct 2, 2005
    #15
  16. otisbrown

    Dan Abel Guest


    I don't think that it is exactly a newsflash to say that a lot of
    posters on newsgroups are into conspiracy theories.
     
    Dan Abel, Oct 2, 2005
    #16
  17. otisbrown

    otisbrown Guest

    Dear Dan,

    I am certainly NOT in to "conspiracy" theories.

    It is very easy to "quick fix" a person with a strong
    minus lens in an office -- in 15 minutes.

    Perhaps most people ONLY what that.

    But there are strong scientific concepts and data
    that suggests that that simple procedure has
    serious "secondary" consequences.

    This truly becomes an "issue" for the person who
    is mature enough to "choose" between the
    secondary-opinion (with exhaustive review of the facts)
    and the majority-opinion, which is easy as pie.

    My "motivation" was to provide a "fighting chance"
    for prevention for my immediate relatives.

    Fair enough?

    Best,

    Otis
     
    otisbrown, Oct 2, 2005
    #17
  18. otisbrown

    LarryDoc Guest

    Liar. You continually accuse doctors of conspiring to suppress *your*
    unfounded theories in support of their evil methods of doing good for
    the visually impaired.
    Liar. There is not one. Prove your statements. You can't. You lie.
    I don't care what your motivation was, but posting the same drivel here
    for three years and having the scientists here continually demonstrate
    that you are wrong, lie, deceive and otherwise do nothing other than to
    embarrass yourself is very, very strange. In fact, sick.

    Someone copy this and put it back under "OTISBROWN WARNING"

    LB
     
    LarryDoc, Oct 2, 2005
    #18
  19. otisbrown

    Dr. Leukoma Guest

    Is that so? What are the suggested and proven consequences. I suggest
    that you word your reply very carefully.
    If a mature person were reading your drivel, they would say that you
    were very immature.
    Your motivation is to drag up whatever old, discarded, disproven
    theories that can be easily recycled to shift the blame from your
    myopic genes onto someone else.

    DrG
     
    Dr. Leukoma, Oct 3, 2005
    #19
  20. otisbrown

    otisbrown Guest

    Dear Mike,


    Please point us to a comparison between people wearing glasses and
    people
    who don't. If you find one, it'll disagree with you.

    Otis> Yes, the Oakley-Young study, were the children wearing
    a +1.5 diopter lens had a "down" rate of approximately
    zero diopters per year, were the single-minus had
    a "down" rate of about -0.52 diopters per year. This
    suggests that a "better educated" person at
    20/50, could gradually "clear" to 20/30 or better
    with intensive use of a stronger plus -- say
    +2.5 diopters -- consistent with the person's
    habitual reading distance. But of course this
    has already been done by the scientist
    Dr. Stirling Colgate.


    You haven't reviewed the facts "exhaustively." You're presented two or
    three
    old papers and LOTS of opinions.

    Otis> There is no doubt that the entire population of natural-eyes
    primates will show a change in refractive state if you
    place a -3 diopter lens on one eye. But it is
    a scientific fact that you will think up some
    reason to ignore all objective facts -- when
    the consequences become obvious.


    Do your relatives read s.m.v.?

    Otis> I have posted our discussions to them -- to
    be very careful about your "prescription" of 20/10
    vision (about a -2 diopter lens) for a child
    with 20/40 vision. Yes -- they have good reason
    to be very careful about what you are doing -- and
    the effect of what you might do to their children.

    Otis> There have been many MDs who have been
    VERY CAUTIOUS with over-prescribing that minus lens,
    but have not been articulate about the reasons for
    there caution. Given the results of the
    Oakley-Young study -- there are very strong
    reasons for that caution. The parents should
    be better-informed of this issue.

    Best,

    Otis
     
    otisbrown, Oct 3, 2005
    #20
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