Developmental Changes in Anterior Corneal Astigmatism in Tohono O’odham Native American Infants and Children

Harvey, Erin M.; Miller, Joseph M.; Schwiegerling, Jim; Sherrill, Duane L.; Messer, Dawn H.; Dobson, Velma

doi:10.3109/09286586.2013.767355

Cited by 8 publications

(10 citation statements)

References 30 publications

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“…The astigmatism is relatively stable from a young age 14 and clearly present before the onset of myopia in most cases.…”

Section: Discussionmentioning

confidence: 97%

“…While there are sometimes minor fluctuations in astigmatic power, anterior corneal astigmatism typically becomes stable by 3 years of age and most astigmatic Tohono O'odham children remain astigmatic throughout childhood. 14 We have assembled a large longitudinal database of refractive error in Tohono O'odham children ranging in age from 3 to 18 years. In the present study, we investigate the hypothesis that degradation of image quality due to refractive astigmatism creates complex cues to emmetropization, resulting in increased rate of spherical equivalent shift towards myopia and increased occurrence of myopia.…”

mentioning

confidence: 99%

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Astigmatism and Myopia in Tohono O’odham Native American Children

Twelker

Miller²,

Sherrill

et al. 2013

Optometry and Vision Science

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Purpose To describe change in spherical equivalent (M) in a longitudinal sample of Tohono O'odham students ages 3 to 18 years and to test the hypothesis that astigmatism creates complex cues to emmetropization, resulting in increased change in M in the direction of increasing myopia and increased occurrence of myopia. Methods Subjects were 777 Tohono O'odham Native American children on whom cycloplegic right eye autorefraction was measured on at least two study encounters between ages 3 and 18 years (first encounter prior to age 5.5 years, final encounter ≥ 3 years later). Regression lines were fit to individual subjects’ longitudinal M data to estimate rate of change in M (regression slope, D/year). Regression was also used to predict if a subject would be myopic (≤−0.75D M) by age 18 years. ANCOVA was used to assess the relation between M slope and magnitude of baseline M and astigmatism. Chi-square analyses were used to assess the relation between predicted myopia onset and magnitude of baseline M and astigmatism. Results Mean M slope was significantly more negative for hyperopes (M ≥ +2.00) than for myopes (M ≤ −0.75) or for subjects neither hyperopic nor myopic (NHM, M > −0.75 and < +2.00), but there was no significant difference between the myopic and NHM groups. Chi-square analysis indicated that final myopia status varied across level of baseline astigmatism. Subjects with high astigmatism were more likely to be predicted to have significant myopia by age 18 years. Conclusions The association between greater shift in M towards myopia with age in subjects who were hyperopic at baseline is consistent with continued emmetropization in the school years. Results regarding predicted myopia development imply that degradation of image quality due to refractive astigmatism creates complex cues to emmetropization, resulting in increased occurrence of myopia.

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“…The astigmatism is relatively stable from a young age 14 and clearly present before the onset of myopia in most cases.…”

Section: Discussionmentioning

confidence: 97%

mentioning

confidence: 99%

Astigmatism and Myopia in Tohono O’odham Native American Children

Twelker

Miller²,

Sherrill

et al. 2013

Optometry and Vision Science

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“…These data extend our previous longitudinal reports on astigmatism in this population to a much larger age range, allowing us to compare results in younger and older school-age children. 7 In addition, we extend our previous cross-sectional analysis of the relation between refractive astigmatism and its components (keratometric and internal astigmatism) in preschoolers to a larger age range and to a longitudinal sample, 9 allowing us to assess the hypothesis that change in internal astigmatism may be negatively correlated with change in amount of keratometric astigmatism, resulting in stable levels of refractive astigmatism with age.…”

mentioning

confidence: 99%

“…1,2,4-7 A longitudinal study of corneal astigmatism in 960 Tohono O'odham children aged 6 months through 7 years showed that in early development (6 months to <3 years), astigmatism decreased in children with high astigmatism (À0.37 diopters [D]/y) and remained stable in children with little or no astigmatism (þ0.05 D/y). 7 From age 3 through 7 years, astigmatism decreased in children with both high astigmatism (À0.11 D/y) and low/no astigmatism (À0.03 D/y). 7 A detailed account of changes in astigmatism beyond age 7 years in this population has not yet been reported.…”

mentioning

confidence: 99%

“…7 From age 3 through 7 years, astigmatism decreased in children with both high astigmatism (À0.11 D/y) and low/no astigmatism (À0.03 D/y). 7 A detailed account of changes in astigmatism beyond age 7 years in this population has not yet been reported. However, a recent report on change in spherical equivalent (M) in a longitudinal sample of Tohono O'odham students ages 3 to 18 years showed that rate of change in M with age was significantly greater for children who were hyperopic (M ‡ þ2.00) prior to age 5.5 years, consistent with continued emmetropization into the school years.…”

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confidence: 99%

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Longitudinal Change and Stability of Refractive, Keratometric, and Internal Astigmatism in Childhood

Harvey¹,

Miller²,

Twelker³

et al. 2014

Investigative Ophthalmology & Visual Science

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PURPOSE. To assess longitudinal change in refractive, keratometric, and internal astigmatism in a sample of students from a population with a high prevalence of with-the-rule (WTR) astigmatism and to determine the optical origins of changes in refractive astigmatism. METHODS.A retrospective analysis of longitudinal measurements of right eye refractive and keratometric astigmatism in Tohono O'odham Native American children was conducted. Changes in refractive and keratometric astigmatism per year were compared in a younger cohort (n ¼ 1594, 3 to <11 years old) and an older cohort (n ¼ 648, 11 to <19 years old). Data were analyzed in clinical notation (Cyl) and vector notation (J0, J45). RESULTS.On average, refractive astigmatism (means: 1.19 diopters [D] Cyl, þ0.54 J0, þ0.03 J45) resulted primarily from WTR corneal astigmatism (means: þ0.85 J0, À0.02 J45) and against-the-rule (ATR) internal astigmatism (means: À0.31 J0, þ0.05 J45). Mean longitudinal changes in astigmatism were statistically significant (younger cohort À0.02 D/y Cyl; older cohort þ0.06 D/y Cyl). In the younger cohort, astigmatism decreased with age in low and moderate astigmats (<3.00 D) and increased with age in high astigmats ( ‡3.00 D). In the older cohort, astigmatism increased with age across all levels of astigmatism. Longitudinal changes in keratometric and internal astigmatism were negatively correlated in both cohorts.CONCLUSIONS. Cross-sectional data suggest the presence of a constant ATR contribution from internal astigmatism (0.60 D Cyl) that is close to the 0.50 D ATR constant reported by Javal and others. Highly astigmatic 3-to <11-year-old children and children older than age 11 years show a small (not clinically significant) increase in astigmatism with age. A negative correlation between changes in keratometric astigmatism and internal astigmatism suggests an active compensation that may contribute to the stability of astigmatism in Tohono O'odham children.Keywords: astigmatism, refractive error development, children, Native American R esearch conducted over the past 15 years has yielded a large longitudinal database on refractive development in Tohono O'odham children. There is a high prevalence of astigmatism among elementary school children who are members of this Native American tribe.1-4 The high prevalence of refractive astigmatism in Tohono O'odham children is present in infancy and persists at least through elementary school. 1,2,4-7 A longitudinal study of corneal astigmatism in 960 Tohono O'odham children aged 6 months through 7 years showed that in early development (6 months to <3 years), astigmatism decreased in children with high astigmatism (À0.37 diopters [D]/y) and remained stable in children with little or no astigmatism (þ0.05 D/y).7 From age 3 through 7 years, astigmatism decreased in children with both high astigmatism (À0.11 D/y) and low/no astigmatism (À0.03 D/y). 7 A detailed account of changes in astigmatism beyond age 7 years in this population has not yet been reported. However, a recent report on change...

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Utility of an open field Shack-Hartmann aberrometer for measurement of refractive error in infants and young children

Harvey

Miller

Schwiegerling

2013

Journal of American Association for Pediatric Ophthalmology and

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PURPOSE To assess the utility of an open-field Shack-Hartmann aberrometer for measurement of refractive error without cycloplegia in infants and young children. METHOD Data included 2698 subject encounters with Native American infants and children aged 6 months to <8 years. We attempted right eye measurements without cycloplegia using the pediatric wavefront evaluator (PeWE) on all participants while they viewed near (50 cm) and distant (2 m) fixation targets. Cycloplegic autorefraction (Rmax [Nikon Retinomax K-plus2]) measurements were obtained for children aged ≥3 years. RESULTS The success rates of noncycloplegic PeWE measurement for near (70%) and distant targets (56%) significantly improved with age. Significant differences in mean spherical equivalent (M) across near versus distant fixation target conditions were consistent with the difference in accommodative demand. Differences in astigmatism measurements for near versus distant target conditions were not clinically significant. Noncycloplegic PeWE and cycloplegic Rmax measurements of M and astigmatism were strongly correlated. Mean noncycloplegic PeWE M was significantly more myopic or less hyperopic and astigmatism measurements tended to be greater in magnitude compared with cycloplegic Rmax. CONCLUSIONS The PeWE tended to overestimate myopia and underestimate hyperopia when cycloplegia was not used. The PeWE is useful for measuring accommodation and astigmatism.

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Developmental Changes in Anterior Corneal Astigmatism in Tohono O’odham Native American Infants and Children

Abstract: The greatest change occurred in highly astigmatic infants and toddlers (0.37 D/year). By age 3 years, change was minimal and not clinically significant. Changes observed were due primarily to change in the J0 component of astigmatism.

Cited by 8 publications

References 30 publications

Astigmatism and Myopia in Tohono O’odham Native American Children

Astigmatism and Myopia in Tohono O’odham Native American Children

Longitudinal Change and Stability of Refractive, Keratometric, and Internal Astigmatism in Childhood

Utility of an open field Shack-Hartmann aberrometer for measurement of refractive error in infants and young children

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