title: All biometric components are important in anisometropia, not just axial length.
abstract: BACKGROUND
  No study to date has looked into the relationship between ocular biometrics with anisometropia exclusively; therefore, the purpose of this study was to determine the relationship between anisometropia and ocular biometrics.
  
  
  METHODS
  In a cross-sectional study with multistage cluster sampling, 6311 people in the 40-64-year-old age group from the population of Shahroud, Iran, were selected. Of these, 5190 people participated in the study. For all participants, tests for visual acuity, cycloplegic and non-cycloplegic refraction, slit lamp test and fundoscopy were performed. All participants underwent biometric examinations using the Allegro Biograph (WaveLight AG, Erlangen, Germany).
  
  
  RESULTS
  Asymmetry of axial length, corneal power, vitreous chamber depth, anterior chamber depth, lens thickness and lens power were significantly more among participants who were anisometropic than those who were non-anisometropic. The correlation of anisometropia with axial length asymmetry was 0.735, 0.273 with corneal power, 0.183 with anterior chamber depth and 0.311 with lens power (p<0.001). In a multiple linear regression model, anisometropia was found to have significant associations with axial length asymmetry (standard coefficient (SC)=0.905), corneal power asymmetry (SC=0.350), lens power asymmetry (SC=0.454), nuclear opacity asymmetry (SC=0.074) and age (SC=0.28) (R(2)=85.1%). According to the linear regression model, corneal power had the strongest association with anisoastigmatism.
  
  
  CONCLUSIONS
  Axial length asymmetry has the strongest correlation with anisometropia; nonetheless, other components of ocular biometrics such as corneal power, lens opacity, lens power and anterior chamber depth are related to anisometropia as well. More than 10% of changes in anisometropia can be explained with changes in factors other than asymmetry of ocular biometrics and lens opacity.
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, , Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khabazkhoob
authors.forename: Mohammad Hassan
authors.initials: MH
authors.lastname: Emamian
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shariati
authors.forename: Tahereh
authors.initials: T
authors.lastname: Abdolahi-nia
authors.forename: Akbar
authors.initials: A
authors.lastname: Fotouhi
mesh_terms: D000328:Adult; D015858:Anisometropia / Q000453:epidemiology / Q000473:pathology*; D001251:Astigmatism / Q000453:epidemiology / Q000473:pathology*; D058452:Axial Length, Eye / Q000473:pathology*; D001699:Biometry / Q000379:methods*; D002386:Cataract / Q000453:epidemiology / Q000473:pathology*; D015331:Cohort Studies; D003315:Cornea / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000453:epidemiology / Q000473:pathology*
keywords: Anterior chamber; Cornea; Epidemiology