title: Longitudinal study of iris concavity, corneal biomechanics, and correlations to ocular biometry in a cohort of 10- to 12-year-old UK schoolboys: 2-year follow-up data.
abstract: OBJECTIVE
  To explore changes in iris curvature over a 2-year period. To investigate associations between iris curvature and ocular biometric parameters. To explore relationships between a number of nonocular measurements and ocular biometric parameters.
  
  
  METHODS
  Schoolboys enrolled 2 years previously were invited to return for anterior segment optical coherence tomography, corneal hysteresis (CH), corneal resistance factor (CRF), and axial biometric measurements. Refractive error was assessed and measures of height, weight, waist circumference, digit ratio, and percentage body fat taken.
  
  
  RESULTS
  Mean spherical equivalent refraction reduced by 0.76 diopters and mean iris concavity, defined as a measurement of less than or equal to -0.1 mm, increased by 0.018 mm at distance fixation and 0.04 mm on accommodation. Compared with 2 years previously, the prevalence of iris concavity increased from 24% to 32% on distance fixation and from 65% to 84% on accommodation. Variables significantly associated with nonaccommodating iris curvature were anterior chamber depth (ACD, P = 0.029) and mean scleral spur angle (P = 0.0001). Variables significantly associated with accommodating iris curvature were ACD (P = 0.02), lens vault (P = 0.047), and scleral spur angle (P < 0.0001). Significant association was again found between CH and accommodating spur-to-spur distance (R(2) = 0.13, P = 0.007).
  
  
  CONCLUSIONS
  Iris concavity was more prevalent in this cohort of schoolboys than 2 years earlier. The degree of concavity remains related to ACD and lens vault. The association between spur-to-spur distance and CH was similar at baseline and after 2 years.
authors.affiliation: National Institute of Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital National Health Service (NHS) Foundation Trust and University College London (UCL) Institute of Ophthalmology, London, United Kingdom.
authors.forename: Ameet
authors.initials: A
authors.lastname: Shah
authors.affiliation: National Institute of Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital National Health Service (NHS) Foundation Trust and University College London (UCL) Institute of Ophthalmology, London, United Kingdom.
authors.forename: Gerassimos
authors.initials: G
authors.lastname: Lascaratos
authors.affiliation: National Institute of Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital National Health Service (NHS) Foundation Trust and University College London (UCL) Institute of Ophthalmology, London, United Kingdom.
authors.forename: David F
authors.initials: DF
authors.lastname: Garway-Heath
authors.affiliation: National Institute of Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital National Health Service (NHS) Foundation Trust and University College London (UCL) Institute of Ophthalmology, London, United Kingdom.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Foster
authors.affiliation: National Institute of Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital National Health Service (NHS) Foundation Trust and University College London (UCL) Institute of Ophthalmology, London, United Kingdom Department of Epidemiology and Genetics, Institute of Ophthalmology, London, United Kingdom.
authors.forename: Keith
authors.initials: K
authors.lastname: Barton
mesh_terms: D000867:Anterior Chamber / Q000473:pathology; D058452:Axial Length, Eye / Q000473:pathology; D001696:Biomechanical Phenomena; D001699:Biometry; D001824:Body Constitution; D002648:Child; D003315:Cornea / Q000502:physiology*; D004548:Elasticity / Q000502:physiology*; D005500:Follow-Up Studies; D006801:Humans; D007498:Iris / Q000473:pathology*; D008297:Male; D009216:Myopia / Q000503:physiopathology; D012029:Refraction, Ocular / Q000502:physiology; D041623:Tomography, Optical Coherence; D006113:United Kingdom; D014792:Visual Acuity / Q000502:physiology
keywords: anterior segment optical coherence tomography; corneal hysteresis; iris concavity; pigment dispersion; refractive error