Effects of refraction and axial length on childhood optic disk parameters measured by optical coherence tomography

PURPOSE: To assess the effects of refraction and axial length on optical coherence tomography (OCT) measures of childhood optic disk parameters. DESIGN: Population-based cross-sectional study. METHODS: Of 4,118 children examined in the Sydney Myopia Study (Sydney Childhood Eye Study) from 34 randomly selected primary schools and 21 secondary schools from 2003 through 2005, 3,529 (85.7%) were included in the analysis (1,395 6-year-old children [year 1 students] and 2,134 12,year,old children [year 7 students]). Comprehensive standardized eye examinations included best-corrected visual acuity, cycloplegic autorefraction, biometry measurements, and fast optic disk scans using OCT. RESULTS: After adjusting for magnification, the mean optic disk area was positively associated with axial length (Pt-nd <.0001, both age groups) but was not associated consistently with spherical equivalent refraction (SER). CONCLUSIONS: Optic disk parameters in childhood are influenced by axial length, but not by refractive error itself.