title: The Heritability of Corneal and Ocular Higher-Order Aberrations in Koreans: The Healthy Twin Study.
abstract: OBJECTIVE
  To estimate the genetic influences on corneal and ocular higher-order aberrations (HoAs) in the Korean population.
  
  
  METHODS
  This was a prospective, family-based twin cohort study. A total of 1272 adult twins and their family members, who were part of the Korean Healthy Twin Study from 2007-2011, were included. Corneal and ocular HoAs were measured. The genetic influences on HoAs were investigated by using variance-component methods after adjusting for age and sex. Narrow-sense heritability was calculated. Intraclass correlation coefficients (ICCs) were used to calculate degrees of resemblance among different types of family relationships.
  
  
  RESULTS
  A total of 269 monozygotic (MZ) twin pairs (including 176 MZ twin pairs and 93 orphan twins), 50 dizygotic (DZ) twin pairs (including 38 DZ twin pairs and 12 orphan twins), and 739 adult first-degree relatives of twins in 358 families were included. For more than half of corneal HoAs, the narrow-sense heritability estimates were not significant. Horizontal coma was highly heritable among corneal HoAs. The ICCs of horizontal coma from MZ twin pairs, pooled first-degree pairs, and spouse pairs were 0.41, 0.05, and 0.00, respectively. Among ocular HoAs, the estimated narrow-sense heritability of SA was 0.71 with the highest estimates. The ICCs of spherical aberration (SA) from MZ twins, pooled first-degree pairs, and spouse pairs were 0.76, 0.25, and 0.06, respectively.
  
  
  CONCLUSIONS
  Both corneal and ocular HoAs demonstrated smaller heritability. Corneal HoAs showed low heritability, suggesting individual environmental factors explain most of the variance of these HoAs in the Korean population. Ocular HoAs were moderately heritable.
authors.affiliation: Department of Ophthalmology Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea 2Department of Preventive Medicine, Catholic University School of Medicine, Seoul, South Korea.
authors.forename: Dong Hui
authors.initials: DH
authors.lastname: Lim
authors.affiliation: Department of Epidemiology, School of Public Health and Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea.
authors.forename: Woori
authors.initials: W
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Gyule
authors.initials: G
authors.lastname: Han
authors.affiliation: Department of Ophthalmology, Sahmyook Medical Center, Seoul, South Korea.
authors.forename: Gi Hyun
authors.initials: GH
authors.lastname: Bae
authors.affiliation: Saevit Eye Hospital, Goyang, South Korea.
authors.forename: Myung Hun
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Asan Medical Center, Ulsan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Myoung Joon
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Family Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Yun-Mi
authors.initials: YM
authors.lastname: Song
authors.affiliation: Department of Ophthalmology Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Eui-Sang
authors.initials: ES
authors.lastname: Chung
authors.affiliation: Department of Ophthalmology Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Tae-Young
authors.initials: TY
authors.lastname: Chung
authors.affiliation: Department of Epidemiology, School of Public Health and Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea.
authors.forename: Joohon
authors.initials: J
authors.lastname: Sung
authors.lastname: Korean Healthy Twin Study
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D044466:Asian People; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000235:genetics*; D004200:Diseases in Twins / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012030:Refractive Errors / Q000235:genetics*; D056910:Republic of Korea; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics; D055815:Young Adult