Myopia Prevalence and Progression (1989) / Chapter Skim
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Appendix C: Review of the Progression Literature
Appendix C: Review of the Progression Literature
Pages 62-88
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From page 62... ...
~ · ~ myopia, In wn1cn one eye opntna~moscop1catly or otherwise snows visible pathological signs, or has substandard corrected visual acuity, or both (Curtin, 1966, 1979~. The studies discussed below deal almost exclusively with myopia progression in simple myopia.
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From page 63... ...
increased, the prevalence of hyperopia remained about the same, the mean refractive error shifted toward hyperopia, and the range and standard deviation of refractive errors decreased. Studies by Mohindra et al.
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From page 64... ...
JUVENILE MYOPIA Typical Changes During the Sthool-age Ye are During the middle of this century, thought on refractive changes was dominated by concepts from cross-sectional and partially longitudinal studies of private practice records (Brown and Kronfeld, 1929; Jackson, 1932; Brown, 1938, 1942; Slataper, 1950~. Cycloplegic refraction was negative in sign from age 6 or 7 until the early 30s, the changes being lower in magnitude after the middle teens.
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From page 65... ...
The studies on age of onset of myopia progression, rates of childhood progression, and age of cessation discussed below are drawn almost exclusively from private practice records of myopes. While this means, of course, selected samples, it is perhaps less of a detriment in studying myopia progression than it would be in studying population characteristics.
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From page 66... ...
Refractive values used were the right eye spherical equivalents as determined by retinoscopy using 1 percent cyclopentolate. The definition of age of myopia onset as used in this study was not given.
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From page 67... ...
67 TABLE C-2 Mean Amount of Myopia at Age 15-16 According to the Age of Myopia Onset Age of myopia Final refraction onset N Mean SD 7-8 Gals 3 -6.17 1.20 Boys 6 -4.42 2.04 9 Gals 8 -4.91 2.52 Boys 9 -4.06 0.95 10 Gals 8 -4.00 1.14 Boys 6 -4.33 0.88 11 Gals 32 -3.27 1.26 Boys 15 -3.00 1.40 12 Gals 34 -2.82 1.06 Boys 15 -2.63 1.14 13 Gals 20 -2.59 0.95 Boys 6 -2.42 - 0.77 14 Gals 16 -2.09 1.18 Boys 12 -2.13 0.94 15 Gals 15 -1.23 0.67 Boys 9 -1.00 0.52 7-10 40 -4.46 1.63 11-13 122 -2.87 1.15 14-15 52 -1.66 1.00 SOURCE: Mansard (1985a)
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From page 68... ...
In the United States, mean rates of childhood myopia progression were in the neighborhood of -0.30 to -0.60 D./yr. (Nolan, 1964; Roberts and Banford, 1967; Baldwin et al., 1969; Oakley and Young, 1975; Goss, 1984)
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From page 69... ...
the retractive data used were refractive errors in the principal meridian nearest horizontal in the right eye as derived from the manifest subjective refraction recordings. Rates of childhood myopia progression in diopters per year were calculated by linear regression, using points at or before age 15 in those cases in which four or more refractions were recorded during that age span.
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From page 70... ...
The cessation age could be viewed as a point of transition from the generally rapid childhood myopia progression to a period of relatively smaller or negligible increases in myopia. The increases in myopia that do occur after the cessation age, especially after ages 1~20, are referred to in this appendix as young adult myopia progression.
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From page 71... ...
~1 4 6 8 10 12 14 16 18 20 22 24 AGE (yrs) FIGURE C-2 Examples of myopia progression in five males (A)
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From page 72... ...
Brown (1942) , in his study compiled from cycloplegic refractions in a private practice, found mean annual refractive error changes that were negative in sign from ages 6 to 34.
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From page 73... ...
Since the initial refraction was at age 13, part of this increase in myopia may have been the continuation of childhood myopia progression before its cessation. None of the individuals who had 1.00 D
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From page 74... ...
or more hyperopia at entrance, only 36 developed myopia of any amount by graduation. There were 624 men with spherical equivalent refractive errors of +0.50 or less who had visual defects at graduation.
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From page 75... ...
presented frequency distributions of spherical equivalent refractive errors for the U.S. Military Academy class of 1974 at the entrance physical examination in 1970
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From page 76... ...
(+ 0.224~. Since these were mean changes over three- to four-year intervals, the mean annual changes would be quite small and would not show as much mean shift toward myopia as other age comparable groups discussed.
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From page 77... ...
77 TABLE C-5 Refractive Error Change In Submariners and National Guardsmen r . Submariners National Guardsmen Age N % N % 22 to 29 at retest More myopic No change More hyperopic Subtotal 30 to 37 at retest More myopic 22 49 7 16 16 36 45 28 34 9 43 6 29 6 29 21 9 46 No change 16 19 7 28 More hyperopic 39 47 9 36 Subtotal 83 25 38 to 45 at retest More myopic No chanage More hyperopic 12 37.5 9 90 8 25 O O 12 37.5 1 10 Subtotal 32 10 More myopic (total)
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From page 78... ...
The study provided a random sample of the number of pilots and navigators required to wear corrective lenses and of initial and current spherical equivalent refractive errors. The study included persons who had entered undergraduate training at ages 20 to 25 and who had server} on active duty for 20 years or less.
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From page 79... ...
Shotwell (1981, 1984) has studied the effects of reading lens prescription on refractive error changes in young adults.
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From page 80... ...
, and time spent on near work versus time spent in outdoor activities. Of the six risk factors, only the time spent on near work versus time spent outdoors showed a statistically significant difference in mean refractive change between the high-risk and low-risk groups.
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From page 81... ...
in the left eye, corresponding to spherical equivalent refractive error changes of -0.94 D in the right eye and -0.75 D
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From page 82... ...
It may be noted that patterns with refractive changes toward myopia were more common among males (see Figure Cab. They calculated rates of young adult myopia progression, using linear regression slopes (D./yr.)
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From page 83... ...
Statistically significant correlations were found between rate of refractive change and rate of keratometer power change for young adult myopia progression. (Significant correlations were not found for childhood myopia progression.)
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From page 84... ...
Some emmetropic young adults also have myopia appear with subsequent young adult myopia progression. As discussed in the next section, the rates of adult myopia progression following adult onset are different from those of childhood myopia progression.
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From page 85... ...
There was great individual variability in refractive error and component changes. The work by Sorsby and his colleagues suggests that myopia appears and childhood myopia progression occurs most often when axial elongation is greater than usual or when average amounts of axial elongation are not adequately compensated for by corneal and lens power reductions.
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From page 86... ...
Considering the total axial length of the eye (i.e., the sum of the anterior chamber depth, axial diameter of the lens, and the length of the vitreous) , Larsen (1971a)
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From page 87... ...
Corneal curvature was measured by keratometry; anterior chamber depth, lens thickness, vitreous depth, and axial length were determined by ultrasonography. Refraction values were spherical equivalents from retinoscopy with 1 percent cyclopentolate and 1 percent cyclopentolate and 1 percent tropicamide.
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From page 88... ...
SOURCE: Pledelius (1981b, 1982a) COMPARISON OF RATES OF MYOPIA PROGRESSION 1lOR ADULT- ONSET AND CHILDHOOD MYOPIA The rates of young adult myopia progression after onset in adulthood are lower than the rates of childhood myopia progression.
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