Associations of Birth Weight With Ocular Biometry, Refraction, and Glaucomatous Endophenotypes: The Australian Twins Eye Study

doi:10.1016/j.ajo.2010.06.028

American Journal of Ophthalmology

Volume 150, Issue 6, December 2010, Pages 909-916.e3

https://doi.org/10.1016/j.ajo.2010.06.028 Get rights and content

Purpose

To examine the relationship of birth weight with ocular measures in a Caucasian twin population.

Design

Cross-sectional study of 1498 twins (308 monozygotic and 441 dizygotic pairs) aged between 5 to 80 years participating in the Australian Twins Eye Study.

Methods

All participants underwent ophthalmic examination including bilateral cycloplegic autorefraction, keratometry, interpupillary distance (IPD), central corneal thickness, intraocular pressure (IOP), and retinal photography. Birth weight and gestation were obtained from a self-administered questionnaire. A subset of the twins also participated in the Tasmanian Infant Health Study (288) and the Childhood Blood Pressure Study (184), which collected data on birth parameters allowing for verification of data. Linear mixed models were used for the main analysis.

Results

Both the within-pair (β_w 0.27, 95% confidence interval [CI] 0.15, 0.38 mm per kg increase in birth weight, P < .001) and between-pair associations (β_B 0.22, 95% CI 0.08, 0.35, P = .002) of birth weight with axial length were significant and of similar magnitude (difference in effect, P = .56), after adjusting for relevant confounders. In contrast, birth weight was negatively associated with corneal curvature (β_w −0.82, 95% CI −1.09, −0.55 diopters per kg increase; β_B −0.69, 95% CI −0.98, −0.41, both P < .001). These associations remained significant within dizygotic and monozygotic pairs. Refraction, anterior chamber depth, IPD, IOP, and optic disc parameters are unrelated to birth weight.

Conclusions

Consistent with previous studies in singleton children, lower birth weight is associated with shorter axial length and more curved corneas in this twin study. This also adds new insights into the emmetropization process.

Section snippets

Study Population

The Australian Twins Eye Study (ATES), involving 2235 twins and nontwin siblings, was designed to investigate the relative influence of genetic and environmental factors on a variety of ocular traits related to glaucoma. The study design and details of sample recruitment are described elsewhere.⁸ In brief, the study population comprising predominantly Caucasian twins were ascertained from the Tasmanian Infant Health Study (TIHS) cohort,⁹ the Brisbane Adolescent Twin Study,6, 10 and the

Results

Selected characteristics including demographic information, birth parameters, and anthropometric measures of the study sample stratified by zygosity are shown in Table 1. The median age of the whole study sample was 17 years (range, 5-80 years). MZ twins (n = 616; 308 pairs) were more likely to be female and older, and a higher proportion were of low birth weight, small for gestational age, and premature than DZ twins (n = 882; 441 pairs). MZ and DZ twins had the same median birth length of 47

Discussion

In this cohort comprising 308 MZ and 441 DZ twin pairs who participated in the ATES, we showed that twins with lower birth weight tended to have shorter axial length and more steeply curved corneas. These associations remained evident even in within-pair assessment of MZ twins, after adjusting for age, gender, gestational age, and other relevant confounders. The between-pair effect of the associations between lower birth weight and shorter axial length and more curved corneas were also

Cong Sun, MD, PhD, is currently a research fellow based at Murdoch Children's Research Institute, Melbourne, Australia. She received her medical degree from Nanjing University, following by a residency in ophthalmology. Dr Sun completed her MPH and then PhD at the University of Melbourne in 2010. Her PhD examined the genetic and environmental determinants of a novel marker for microvascular changes associated with systemic vascular diseases. Her research interests extend to cardiovascular

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Cited by (25)

Association of birth weight with corneal aberrations in adulthood – Results from a population-based study
2023, Journal of Optometry
Citation Excerpt :
Our data are additionally restricted because self-reported birth weight data were not validated by review of medical records for all participants. In order to ensure a high validity of self-reported birth weight data in our analyses we asked every study participant at study invitation to review personal records or family albums for recorded birth weight data and previous authors found a high reliability of self-reported birth weight10 thus we assume that this is a valid parameter in our study. In addition, we compared self-reported birth weight of a subsample of participants (n = 86) born in the UMCM.
Low birth weight (BW) is associated with increased corneal aberrations in childhood and alterations of corneal geometry in adulthood. Increased corneal aberrations may be a factor contributing to decreased visual function in former low BW newborns in later life. Hence, the aim of this study was to analyze the long-term effect of low BW on corneal aberrations in adulthood.
In the German population-based Gutenberg Health Study (GHS) participants (age: 40–80 years) were examined with Scheimpflug imaging (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany). The relationship between self-reported BW and the different types of corneal aberrations was analyzed using linear regression analysis as uni- and multivariable analysis with adjustment for potential confounders. The main outcome measures were corneal aberrations defined as astigmatism (Z₂⁻²; Z₂²), coma (Z₃⁻¹; Z₃¹), trefoil (Z₃⁻³; Z₃³), spherical aberration (Z₄⁰) and root-mean square of higher order aberrations (HOA; 3rd up to 8th order; aperture size: 6 mm).
Overall, 5,628 participants were included in this analysis (3,004 women, aged 56.0 +/- 10.3 years). In a multivariable analysis lower BW was associated with decreased horizontal trefoil (B = 0.004 [0.001; 0.006] µm/500 g; p=.008); higher spherical aberrations (B=-0.006 [-0.008;-0.003] µm/500 g; p<.001), higher RMS (B=-0.028 [-0.042;-0.014] µm/500 g; p<.001), increased HOA (B=-0.007 [-0.010;-0.003] µm/500 g; p<.001) and increased LOA (B=-0.027 [-0.041;-0.013] µm/500 g; p<.001). No association was observed between birth weight and the other types of corneal aberrations in multivariable model.
Our results indicate an association between BW and spherical aberration in adults aged 40 to 80 years. This indicates that low BW may have an association with an altered corneal shape development which may affect optical image quality and, hence, visual function.
The relationship of ocular geometry with refractive error in normal and low birth weight adults
2021, Journal of Optometry
Citation Excerpt :
They found in low birth weight children a steeper corneal curvature27,28 and smaller axial length.27 In congruence, in our recent report18 and data of Sun and colleagues of the Australian Twin Study29 it was demonstrated that steeper corneal shape and smaller axial length in former low birth weight individuals seem to persist until adulthood. In contrast to our results, no association between low birth weight and refraction was reported in a twin study in participants aged from 18 to 86 years30 and in another study in participants aged 5–80 years.29
Low birth weight (BW) individuals have an increased risk for myopic refractive error. However, it is unclear which ocular geometric alterations lead to an increase in myopic refractive error. This study aims to evaluate the impact of ocular biometry in interaction with BW on refractive error.
Participants of the prospective, observational, population-based Gutenberg Health Study (GHS) with self-reported BW aged 40–80 years and objective refraction and optical biometry were included. Linear regression analyses were conducted to evaluate associations between spherical equivalent with corneal power, anterior chamber depth, lens thickness and axial length and its interaction with BW adjusted for age and sex. Low BW was defined as BW<2500 g and normal BW between 2500−4000 g.
Overall, 5123 participants were included. Linear regression showed an interaction of axial length (B = 0.009/100 g, p = 0.002) with BW on spherical equivalent while corneal power, anterior chamber depth and lens thickness revealed no interaction with BW on refractive error. Furthermore, linear regression analysis revealed, that axial length explains 58% of variance of spherical equivalent in low BW subjects, and 54% in normal BW subjects. In contrast, corneal power explained 1% of variance of spherical equivalent in both groups.
Our results indicate that axial length variation explains the majority of variance in refractive error, while steeper corneal shape has no conclusive effects on refractive error. Low BW is not linked to effects of steeper corneal shape on myopic refractive error, while the effect of axial length on myopia is fractionally enlarged in those subjects.
Body stature growth trajectories during childhood and the development of myopia
2013, Ophthalmology
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.
Prospective analysis in a birth cohort.
Children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC) U.K. birth cohort (minimum N = 2676).
Growth trajectories between birth and 10 years were modeled from a series of height and weight measurements (N = 6815). Refractive error was assessed by noncycloplegic autorefraction at ages 11 and 15 years (minimum N = 4737). Axial length (AXL) and radius of corneal curvature were measured with an IOLMaster (Carl Zeiss Meditec, Welwyn Garden City, U.K.) at age 15 years (minimum N = 2676). Growth trajectories and an allelic score for 180 genetic variants associated with adult height were tested for association with refractive error and eye size.
Noncycloplegic autorefraction at ages 11 and 15 years, and AXL and corneal curvature at age 15 years.
Height growth trajectory during the linear phase between 2.5 and 10 years was negatively associated with refractive error at 11 and 15 years (P<0.001), but explained <0.5% of intersubject variation. Height and weight growth trajectories, especially shortly after birth, were positively associated with AXL and corneal curvature (P<0.001), predicting 1% to 5% of trait variation. Height growth after 2.5 years was not associated with corneal curvature, whereas the association with AXL continued up to 10 years. The height allelic score was associated with corneal curvature (P = 0.03) but not with refractive error or AXL.
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.
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Ocular geometry in adults born small, appropriate or large for gestational age at term
2024, Acta Ophthalmologica
Ocular geometry in adults born extremely, very and moderately preterm with and without retinopathy of prematurity: results from the Gutenberg Prematurity Eye Study
2023, British Journal of Ophthalmology
Corneal Aberrations and Thickness in Adults Born Small, Appropriate, or Large for Gestational Age at Term
2022, Journal of Clinical Medicine

View all citing articles on Scopus

Professor Mackey has extensively studied large pedigrees with Leber Hereditary Optic Neuropathy. Creating one of the world's largest glaucoma biobanks, his Glaucoma Inheritance Study in Tasmania has helped define phenotype-genotype correlations in myocilin and other glaucoma genes. The Twins Eye Study in Tasmania and Brisbane is investigating the genetic environmental basis on ocular biometry related to glaucoma and myopia. He also leads the Norfolk Island Eye Study and the Western Australian Raine Eye Health Study.

: Supplemental Material available at AJO.com.

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Original articleAssociations of Birth Weight With Ocular Biometry, Refraction, and Glaucomatous Endophenotypes: The Australian Twins Eye Study

Purpose

Design

Methods

Results

Conclusions

Section snippets

Study Population

Results

Discussion

Ophthalmology

Lancet

Fetal origins of coronary heart disease

BMJ

Developmental antecedents of cardiovascular disease: a historical perspective

J Am Soc Nephrol

The relation between birth size and the results of refractive error and biometry measurements in children

Br J Ophthalmol

Impact of birth parameters on eye size in a population-based study of 6-year-old Australian children

Am J Ophthalmol

Effect of birth parameters on retinal vascular caliber: the Twins Eye Study in Tasmania

Hypertension

Twins Eye Study in Tasmania (TEST): Rationale and methodology to recruit and examine twins

Twin Res Hum Genet

Tobacco smoke exposure at one month of age and subsequent risk of SIDS—a prospective study

Am J Epidemiol

Brisbane adolescent twin study: Outline of study methods and research projects

Aust J Psychol

The Australian Twin Registry

Twin Res

Maternal calcium supplementation and cardiovascular risk factors in twin offspring

Int J Epidemiol

Low Birthweight: Country, Regional and Global Estimates

Original article
Associations of Birth Weight With Ocular Biometry, Refraction, and Glaucomatous Endophenotypes: The Australian Twins Eye Study