title: Corneal biomechanics, retinal nerve fiber layer, and optic disc in children.
abstract: OBJECTIVE
  To evaluate the possible associations between corneal biomechanical parameters, optic disc morphology, and retinal nerve fiber layer (RNFL) thickness in healthy white Spanish children.
  
  
  METHODS
  This cross-sectional study included 100 myopic children and 99 emmetropic children as a control group, ranging in age from 6 to 17 years. The Ocular Response Analyzer was used to measure corneal hysteresis (CH) and corneal resistance factor. The optic disc morphology and RNFL thickness were assessed using posterior segment optical coherence tomography (Cirrus HD-OCT). The axial length was measured using an IOLMaster, whereas the central corneal thickness was measured by anterior segment optical coherence tomography (Visante OCT).
  
  
  RESULTS
  The mean (±SD) age and spherical equivalent were 12.11 (±2.76) years and -3.32 (±2.32) diopters for the myopic group and 11.88 (±2.97) years and +0.34 (±0.41) diopters for the emmetropic group. In a multivariable mixed-model analysis in myopic children, the average RNFL thickness and rim area correlated positively with CH (p = 0.007 and p = 0.001, respectively), whereas the average cup-to-disc area ratio correlated negatively with CH (p = 0.01). We did not observe correlation between RNFL thickness and axial length (p = 0.05). Corneal resistance factor was only positively correlated with the rim area (p = 0.001). The central corneal thickness did not correlate with the optic nerve parameters or with RNFL thickness. These associations were not found in the emmetropic group (p > 0.05 for all).
  
  
  CONCLUSIONS
  The corneal biomechanics characterized with the Ocular Response Analyzer system are correlated with the optic disc profile and RNFL thickness in myopic children. Low CH values may indicate a reduction in the viscous dampening properties of the cornea and the sclera, especially in myopic children.
authors.affiliation: *PhD †MSc Department of Optics (IB-G, AG-S) and Department of Surgery (EE-G), University of Valencia, Valencia, Spain; Foundation for the Visual Quality (Fundación para la Calidad Visual, FUNCAVIS), Alicante, Spain (DPP-L); Department of Optics, Pharmacology, and Anatomy, University of Alicante, Alicante, Spain (DPP-L); Fisabio Oftalmología Médica (FOM), Valencia, Spain (AL-A); and University Hospital La Fe, Valencia, Spain (EE-G).
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Bueno-Gimeno
authors.forename: Andres
authors.initials: A
authors.lastname: Gene-Sampedro
authors.forename: David P
authors.initials: DP
authors.lastname: Piñero-Llorens
authors.forename: Aitor
authors.initials: A
authors.lastname: Lanzagorta-Aresti
authors.forename: Enrique
authors.initials: E
authors.lastname: España-Gregori
mesh_terms: D000293:Adolescent; D058452:Axial Length, Eye; D001696:Biomechanical Phenomena / Q000502:physiology; D002648:Child; D003315:Cornea / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009412:Nerve Fibers; D009898:Optic Disk / Q000033:anatomy & histology*; D012165:Retinal Ganglion Cells / Q000166:cytology*; D013030:Spain; D041623:Tomography, Optical Coherence; D044465:White People