Refractive Errors in Twin Studies

Abstract

It is estimated that 1.6 billion people worldwide have myopia, a refractive error, and this number is expected to increase to approximately 2.5 billion by the year 2020. It is now well established that both the environment and genetics play a role in the development of myopia. However, the exact contribution of each of these components to myopia development has yet to be completely determined. Twin studies (classical twin model) are commonly used to determine the weighting of genetic and environmental components in disease. Over the last century, twin studies have investigated the heritability of refractive errors in different sample populations and have collectively supported a genetic basis to refractive errors. However, different sample populations and methods of data collection have produced a wide range of heritability estimates ranging from .5 to .9. This article will review those twin studies that have investigated refractive error, particularly myopia, as well as biometric measures linked to refractive error, to compare heritability estimates and methodology designs.

Role of Genetic Factors in Lower- and Higher-Order Aberrations – The Genes in Myopia Twin Study

“…The GEM twin study supports previous twin studies that found a major genetic component for lower-order aberrations (defocus) [14] , with intra-pair correlations for lower-order aberration being significantly higher in MZ compared to those in DZ twin pairs. The heritability of SE was also obtained using all twins in the GEM twin study (n = 612 twin pairs), which was as high as 80%; refer to Dirani et al [16] for heritability estimates for SE.…”

“…Family and twin studies have provided support for a genetic basis to lower-order aberrations (refraction), with family studies showing a significantly higher risk of developing myopia in children with myopic parents compared to children with no myopic parents [14] . Twin studies have also supported a major role for genetic factors in refraction where a significantly higher intra-pair correlation for refraction in monozygotic (MZ) twin pairs (r = 0.80) was found compared to that in dizygotic (DZ) twin pairs (r !…”

Hubungan Status Refraksi, dengan Kebiasaan Membaca, Aktivitas di Depan Komputer, dan Status Refraksi Orang Tua pada Anak Usia Sekolah Dasar

“…Faktor genetik dapat mkan secara rutin dan dalam waktu yang lama banyak didapenurunkan sifat miopia ke keturunannya baik secara autosomal dominan maupun resesif (11,12) dan terdapat hubungan yang signifikan antara status refraksi orang tua dengan keturunannya (13-DISKUSI 15). Pada penelitian ini diperoleh hasil bahwa pada siswa Hasil penelitian ini tidak menunjukkan perbedaan jumlah miopia, hiperopia dan astigmatisma didapatkan status antara status refraksi dengan jenis kelamin maupun refraksi yang sama pada orang tuanya, terutama pada rentang usia tertentu.…”

Myopia, Light and Circadian Rhythms

“…Both genetic and environmental factors have been implicated in the aetiology of myopia. Children with myopic parents have a higher than normal risk of developing myopia (Mutti, Mitchell et al 2002) and twin studies show a higher level of concordance of common myopia in monozygotic compared to dizygotic twins (Dirani, Chamberlain et al 2006). However, the rapid rise in myopia prevalence over recent decades argues strongly that changing environmental factors also play an important role in the aetiology of myopia.…”