Correlation ametropia and component ametropia

Sorsby, Arnold; Leary, George A.; Richards, Mel

doi:10.1016/0042-6989(62)90039-1

Cited by 72 publications

(52 citation statements)

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“…However, despite the appeal of this line of reasoning, and the attraction of axial length as an endophenotype for refractive error 60 , recent results in an animal model of myopia suggest that the genetic variants that influence overall body size and eye size might be distinct from those that confer susceptibility to myopia 26,61 . Moreover, cross-sectional studies in both children and adults demonstrate that the relationship between axial length and refractive error is not "one-toone" in nature, as exemplified by the large range of axial lengths observed in emmetropes, and the observed correlations between refractive error and both crystalline lens and corneal growth trajectories 10,37,[61][62][63] . The findings here also suggest that -at the level of the individual -the genetic variants found to influence height in adulthood might not be predictive of myopia development to any useful extent.…”

Section: Discussionmentioning

confidence: 99%

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Body Stature Growth Trajectories during Childhood and the Development of Myopia

et al. 2013

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Purpose-Stature at a particular age can be considered the cumulative result of growth during a number of preceding growth trajectory periods. We investigated whether height and weight growth trajectories from birth to age 10 years were related to refractive error at ages 11 and 15 years, and eye size at age 15 years. Design-Prospective analysis in a birth cohort.Participants-Children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC) United Kingdom birth cohort (minimum N=2,676).Methods-Growth trajectories between birth and 10 years were modeled from a series of height and weight measurements (N=6,815). Refractive error was assessed by non-cycloplegic autorefraction at ages 11 and 15 years (minimum N=4,737). Axial length and radius of corneal curvature were measured with an IOLmaster at age 15 years (minimum N=2,676). Growth trajectories, and an allelic score for 180 genetic variants associated with adult height, were tested for association with refractive error and eye size.Main outcome measures-Non-cycloplegic autorefraction at ages 11 and 15 years, and axial length and corneal curvature at age 15 years.Results-Height growth trajectory during the linear phase between 2.5-10 years was negatively associated with refractive error at 11 and 15 years (P<0.001), but explained <0.5% of inter-subject variation. Height and weight growth trajectories, especially shortly after birth, were positively associated with axial length and corneal curvature (P<0.001), predicting 1-5% of trait variation. Height growth after 2.5 years was not associated with corneal curvature, whilst the association with axial length continued up to 10 years. The height allelic score was associated with corneal curvature (P=0.03) but not with refractive error or axial length.Address for correspondence and requests for reprints: Dr Kate Northstone, Department of Social Medicine, Oakfield House, Oakfield Grove, Clifton, Bristol, BS8 1TQ, UK, Tel: +44 (0) Conclusions-Up to the age of 10 years, shared growth mechanisms contribute to scaling of eye and body size but minimally to the development of myopia.

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Section: Discussionmentioning

confidence: 99%

“…In emmetropic eyes, a long axial length is generally offset by a flatter cornea 9,37 . In humans and animal models there is evidence that these two major determinants of refractive error are co-ordinately regulated by genetic means 26,38,39 .…”

Section: Introductionmentioning

confidence: 99%

Body Stature Growth Trajectories during Childhood and the Development of Myopia

et al. 2013

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“…Studies, in humans and animal models, have shown how this increased axial length is predominantly a consequence of increased vitreous chamber depth, rather than marked changes in any other ocular component parameter such as anterior chamber depth or lens thickness (2,3). The prevalence of human high myopia (usually defined as eyes with Ͼ6 dioptres (D) of myopia, or Ͼ26 mm in length) is ϳ2% in the general population (1) and it is well documented that individuals with high myopia have a greatly increased risk of ocular pathology (4).…”

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confidence: 99%

Collagen Gene Expression and the Altered Accumulation of Scleral Collagen during the Development of High Myopia

Gentle

Liu

Martin

et al. 2003

Journal of Biological Chemistry

168

120

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The development of high myopia is associated with reduced scleral collagen accumulation, scleral thinning, and loss of scleral tissue, in both humans and animal models. Reduced collagen fibril diameter is also observed in the sclera of eyes with high myopia. The present study investigated aspects of scleral collagen synthesis and degradation, in a mammalian model of high myopia, to elucidate the factors underlying scleral changes. General synthesis and degradation of scleral collagen was investigated in monocularly deprived tree shrews, through the in vivo administration of [ 3 H]proline and subsequent assay of scleral tissue for [ 3 H]collagen. In addition, PCR enriched cDNA, produced from tree shrew scleral mRNA, was used to synthesize probes for hybridization to custom gene arrays consisting of partial sequences for 11 collagen subtypes. Finally, realtime reverse transcriptase-PCR was employed to investigate collagen type I, III, and V mRNA expression in the sclera of myopic, contralateral control, and normal tree shrew eyes. Scleral [ 3 H]proline incorporation was reduced at the posterior pole of myopic eyes following 5 days of monocular deprivation (؊36 ؎ 4%), whereas [ 3 H]proline content was similar in treated and control eyes before myopia induction (؊1 ؎ 8%) but was reduced in myopic eyes following 5 (؊8 ؎ 2%), 12 (؊15 ؎ 4%), and 24 (؊10 ؎ 4%) days of myopia induction. The majority of the collagens investigated were found to be expressed in the sclera, with 11 subtypes being identified. Collagen type I mRNA expression was reduced in the sclera of myopic eyes (؊20 ؎ 7%), however, collagen type III (؉2 ؎ 9%) and type V (؊1 ؎ 6%) expression was unchanged relative to control, resulting in a net increase in the ratio of expression of collagen type III/type I and collagen type V/type I (22 and 25%, respectively). These results show that reduced scleral collagen accumulation in myopic eyes is a result of both decreased collagen synthesis and accelerated collagen degradation. Furthermore, changes in collagen synthesis are driven by reduced type I collagen production. Short term increases in the ratio of newly synthesized collagen type III/type I and type V/type I are likely to be important in the increasing frequency of small diameter scleral collagen fibrils observed in high myopia and may be important in the subsequent development of posterior staphyloma in humans with pathological myopia.The refractive power of the eye is correlated with ocular axial length and it is well established that myopia is caused by increased axial eye size (1). Studies, in humans and animal models, have shown how this increased axial length is predominantly a consequence of increased vitreous chamber depth, rather than marked changes in any other ocular component parameter such as anterior chamber depth or lens thickness (2, 3). The prevalence of human high myopia (usually defined as eyes with Ͼ6 dioptres (D) of myopia, or Ͼ26 mm in length) is ϳ2% in the general population (1) and it is well documented that individuals with high my...

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“…Corneal astigmatism is mainly due to an aspheric corneal anterior surface [Sheridan & Douthwaite, 1989] . In 10% of people the effect is neutralized by the back surface [Sheridan & Douthwaite, 1989;Sorsby et al, 1966;Sorsby et al, 1962]. The curvature of the back surface of the cornea is not considered in most studies because it is more difficult to measure.…”

Section: Epidemiology -Prevalencementioning

confidence: 99%

“…Values greater than 1.00 D represent significant irregularity, though this may be an arbitrary boundary whose value may be determined by further experience with this standardized measurement gauge [Goggin et al, 2000] Astigmatism results from uneven or irregular curvature of the cornea or lens. Corneal and noncorneal factors contribute to total astigmatism [Van Alphen, 1961;Tronn, 1940;Sorsby, Leary & Richards, 1962;Curtin, 1985]. Corneal astigmatism is mainly due to an aspheric corneal anterior surface [Sheridan & Douthwaite, 1989] .…”

Section: Epidemiology -Prevalencementioning

confidence: 99%

Astigmatism – Definition, Etiology, Classification, Diagnosis and Non-Surgical Treatment

Kaimbo¹

2012

Astigmatism - Optics, Physiology and Management

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Correlation ametropia and component ametropia

Cited by 72 publications

References 1 publication

Body Stature Growth Trajectories during Childhood and the Development of Myopia

Body Stature Growth Trajectories during Childhood and the Development of Myopia

Collagen Gene Expression and the Altered Accumulation of Scleral Collagen during the Development of High Myopia

Astigmatism – Definition, Etiology, Classification, Diagnosis and Non-Surgical Treatment

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