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Central corneal thickness is highly heritable: the twin eye studies
Tze'Yo Toh1, S H Melissa Liew, Jane R MacKinnon
1University of Tasmania, The Eye Hospital, Launceston, Australia.
Investigative Ophthalmology & Visual Science
|September 28, 2005
Summary
Central corneal thickness (CCT) is highly heritable, with genetic factors accounting for 95% of its variation. This finding highlights the significant role of genetics in CCT, an important measure for glaucoma assessment.
Area of Science:
- Ophthalmology
- Genetics
- Twin Studies
Background:
- Central corneal thickness (CCT) is a critical biometric parameter in ophthalmic evaluations, particularly for glaucoma risk assessment.
- Understanding the determinants of CCT, including genetic and environmental influences, is essential for accurate diagnosis and management.
Purpose of the Study:
- To determine the heritability of central corneal thickness (CCT) using a classic twin study design.
- To quantify the contribution of genetic factors to individual differences in CCT.
Main Methods:
- A cohort of 256 twin pairs (131 monozygotic, 125 dizygotic) was recruited from Australia and the U.K.
- Central corneal thickness (CCT) was measured using ultrasound pachymetry.
- Structural equation modeling was employed to analyze CCT concordance between twin types and estimate heritability.
Main Results:
- The mean CCT across all participants was 544.5 ± 37.3 µm.
- Intraclass correlation coefficients for CCT were significantly higher in monozygotic twins (0.95) compared to dizygotic twins (0.52).
- A model incorporating additive genetic and unique environmental effects indicated a heritability estimate of 0.95 (95% CI, 0.93–0.96) for CCT.
Conclusions:
- Genetic factors play a predominant role in determining central corneal thickness (CCT).
- The high heritability of CCT (0.95) underscores its strong genetic basis.
- These findings have implications for understanding glaucoma susceptibility and the genetic architecture of ocular traits.
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