title: Abnormal radial deformation hyperacuity in children with strabismic amblyopia.
abstract: OBJECTIVE
  In infants and toddlers, letter acuity is not a useful option, and grating acuity may underestimate the depth of strabismic amblyopia. Here, as a first step to establish the effectiveness of the paradigm as a clinical test, we assessed if radial deformation hyperacuity, known to be severely disrupted in adults with strabismic amblyopia, could be a potential test to detect and monitor strabismic amblyopia in young children.
  
  
  METHODS
  Fifty-one strabismic children and 130 normal controls ages 3 to 17 years participated. Radial deformation hyperacuity with three different radial frequency (RF) patterns (1° radius 8 RF, 0.5° radius 8 RF, and 1° radius 16 RF), optotype acuity, and grating acuity were measured. For strabismic children, hyperacuity and grating acuity were identified as normal/amblyopic based on age-matched norms. The normal/abnormal classification was compared with amblyopia diagnosis by gold standard early treatment diabetic retinopathy study (ETDRS) optotype visual acuity.
  
  
  RESULTS
  The 0.5° radius 8 RF pattern had 83% sensitivity and 71% positive predictive value (PPV) for strabismic amblyopia. In comparison, the 1° radius 8 RF and 1° radius 16 RF patterns had poorer sensitivity (27%-12%) and PPV (57%-50%) for amblyopia, similar to grating acuity (sensitivity = 38%, PPV = 31%). Amblyopic deficits using the 0.5° radius 8 RF pattern were directly proportional to optotype visual acuity deficits.
  
  
  CONCLUSIONS
  The demonstrated feasibility of radial deformation stimuli for forced-choice preferential looking testing and the sensitivity and specificity of the small radius radial deformation hyperacuity stimulus for amblyopia support the potential to utilize this test to detect and monitor amblyopia in infants and preschool children.
authors.affiliation: Retina Foundation of Southwest, Dallas, Texas 75231-0920, USA. vsubramanian@retinafoundation.org
authors.forename: Vidhya
authors.initials: V
authors.lastname: Subramanian
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Morale
authors.forename: Yi-Zhong
authors.initials: YZ
authors.lastname: Wang
authors.forename: Eileen E
authors.initials: EE
authors.lastname: Birch
mesh_terms: D000293:Adolescent; D000550:Amblyopia / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D013285:Strabismus / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D014792:Visual Acuity