title: Should we add visual acuity ratios to referral criteria for potential cerebral visual impairment?
abstract: OBJECTIVE
  To determine whether the assessment of visual acuity ratios might improve the referral of children with (sub)normal visual acuity but at risk of cerebral visual impairment.
  
  
  METHODS
  In an exploratory study, we assessed visual acuity, crowding ratio and the ratios between grating acuity (Teller Acuity Cards-II) and optotype acuity (Cambridge Crowding Cards) in 60 typically developing school children (mean age 5y8m±1y1m), 21 children with ocular abnormalities only (5y7m±1y9m) and 26 children with (suspected) brain damage (5y7m±1y11m). Sensitivities and specificities were calculated for targets and controls from the perspective of different groups of diagnosticians: youth health care professionals (target: children with any visual abnormalities), ophthalmologists and low vision experts (target: children at risk of cerebral visual impairment).
  
  
  RESULTS
  For youth health care professionals subnormal visual acuity had the best sensitivity (76%) and specificity (70%). For ophthalmologists and low vision experts the crowding ratio had the best sensitivity (67%) and specificity (79 and 86%).
  
  
  CONCLUSIONS
  Youth health care professionals best continue applying subnormal visual acuity for screening, whereas ophthalmologists and low vision experts best add the crowding ratio to their routine diagnostics, to distinguish children at risk of visual impairment in the context of brain damage from children with ocular pathology only.
authors.affiliation: Intellectual Disability Medicine, Department of General Practice, Erasmus University Medical Center, Rotterdam, The Netherlands; Royal Dutch Visio, Dutch Centre of Excellence for Visually Impaired and Blind People, The Netherlands. Electronic address: ymievanderzee@visio.org.
authors.forename: Ymie J
authors.initials: YJ
authors.lastname: van der Zee
authors.affiliation: Department of Neuropsychology & Psychopharmacology, University Maastricht, Maastricht, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Stiers
authors.affiliation: Intellectual Disability Medicine, Department of General Practice, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Heleen M
authors.initials: HM
authors.lastname: Evenhuis
mesh_terms: D001927:Brain Diseases / Q000150:complications* / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D012017:Referral and Consultation / Q000592:standards; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000175:diagnosis*; D014787:Vision Tests / Q000379:methods*; D014792:Visual Acuity
keywords: Agudeza visual; Brain damage; Criterios de derivación; Daño cerebral; Ratios de agudeza visual; Referral criteria; Visual acuity; Visual acuity ratios