Predicting Refractive Astigmatism: A Suggested Simplification of Javalʼs Rule

Grosvenor, Theodore; Quintero, Sam; Perrigin, David

doi:10.1097/00006324-198804000-00009

Cited by 52 publications

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“…In the present study, the constant for subjects with clinically significant WTR astigmatism (subjects with refractive J0 ‡ 0.50, equivalent to 1.00 D WTR astigmatism in clinical notation) is approximately À0.25 D of J0 (equivalent to 0.50 D ATR astigmatism in clinical notation). These results are consistent with modifications of Javal's rule specifying that the relation between keratometric astigmatism and refractive astigmatism is best described as magnitude of keratometric astigmatism minus an ATR constant of 0.50 D. 10 The ATR internal astigmatism constant appeared to ''compensate'' for WTR keratometric astigmatism in the present study, resulting in lower levels of WTR refractive astigmatism. However, because the magnitude of internal astigmatism is not negatively correlated with the magnitude of keratometric astigmatism, the data suggest a consistent ATR contribution from internal astigmatism-a passive compensation that can be attributed to the fact that our sample consists primarily of children with high WTR keratometric astigmatism.…”

Section: Relation Between J0 Keratometric Astigmatism and J0 Internalsupporting

confidence: 91%

“…Magnitude of internal astigmatism was close to the 0.50 D ATR constant reported by Javal and others. 10,11 Internal astigmatism was consistent across age groups (Table 1) and magnitude of keratometric astigmatism (Table 3); and 4. Changes with age in keratometric and internal J0 were negatively correlated in both cohorts, suggesting that changes in internal astigmatism may actively compensate for changes in keratometric astigmatism and contribute to the overall stability of WTR refractive astigmatism in childhood (Table 6).…”

Section: Discussionmentioning

confidence: 82%

“…In Tohono O'odham preschool children, magnitude of refractive (total) astigmatism tends to be less than that of keratometric astigmatism due to approximately 0.75 D against-the-rule (ATR) internal astigmatism. 9 This relation, specifically the relation between keratometric and refractive (total) astigmatism, was originally described by Javal in 1890 10,11 : Refractive Astigmatism ¼ 1.25(Keratometric Astigmatism) À 0.50 D 3 90.…”

mentioning

confidence: 99%

“…10 Little is known about how the relation between keratometric and internal astigmatism changes with development in childhood. For example, it is not known if magnitude of ATR Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc. www.iovs.org j ISSN: 1552-5783 internal astigmatism remains constant with age or if it is correlated with changes in keratometric astigmatism.…”

mentioning

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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Section: Relation Between J0 Keratometric Astigmatism and J0 Internalsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 82%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

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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show abstract

“…Corneal astigmatism was plotted against total astigmatism for the different pupil sizes and the relationship between corneal and total astigmatism was found to be independent of pupil size. The results from this study supported Javal's rule as simplified by Grosvenor, Quintero and Perrigin (1988).…”

Section: Corneal and Internal Astigmatismsupporting

confidence: 80%

A review of astigmatism and its possible genesis

Read

Collins

Carney

2007

Clinical and Experimental Optometry

234

205

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Astigmatism is a refractive condition encountered commonly in clinical practice. This review presents an overview of research that has been carried out examining various aspects of this refractive error. We examine the components of astigmatism and the research into the prevalence and natural course of astigmatic refractive errors throughout life. The prevalence of astigmatism in various ethnic groups and diseases and syndromes is also discussed. We highlight the extensive investigations that have been conducted into the possible aetiology of astigmatism, however, no single model or theory of the development of astigmatism has been proven conclusively. Theories of the development of astigmatism based on genetics, extraocular muscle tension, visual feedback and eyelid pressure are considered. Observations and evidence from the literature supporting and contradicting these hypotheses are presented. Recent advances in technology such as wavefront sensors and videokeratoscopes have led to an increased understanding of ocular astigmatism and with continued improvements in technology, our knowledge of astigmatism and its genesis should continue to grow.

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Astigmatismuskorrektur nach Keratoplastik

Langenbucher,

Schrecker

2024

Springer Reference Medizin

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Predicting Refractive Astigmatism: A Suggested Simplification of Javalʼs Rule

Cited by 52 publications

References 0 publications

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

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

A review of astigmatism and its possible genesis

Astigmatismuskorrektur nach Keratoplastik

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