title: Visual functions and interocular interactions in anisometropic children with and without amblyopia.
abstract: OBJECTIVE
  In uncorrected anisometropia, protracted dichoptic stimulation may result in interocular inhibition, which may be a contributing factor in amblyopia development. This study investigates the relationship between interocular interactions and anisometropic amblyopia.
  
  
  METHODS
  Three visual functions (low-contrast acuity, contrast sensitivity, and alignment sensitivity) were measured in the nondominant eye of 44 children aged 5 to 11 years: 10 with normal vision, 17 with anisometropia without amblyopia, and 17 with anisometropic amblyopia. The dominant eye was either fully or partially occluded. The difference in nondominant eye visual function between the full-and partial-occlusion conditions was termed the interaction index. The index of each visual function was compared between subject groups. A higher index indicates stronger inhibition of nondominant eye function with partial occlusion of the dominant eye. Amblyopic children had 6 months of therapy (refractive correction and occlusion), and the reduction in interocular difference in high-contrast acuity was regarded as the treatment outcome. The relationships of the interaction index with the degree of anisometropia, the severity of amblyopia, and the treatment outcomes were examined.
  
  
  RESULTS
  The acuity interaction index was significantly higher in anisometropic children with amblyopia than in those without (P = 0.003). It was positively correlated with the degree of anisometropia (r(s) = 0.35, P = 0.042) and the amblyopic treatment outcomes (r(s) = 0.54, P = 0.038). No such difference or association was found between the contrast sensitivity or alignment sensitivity interaction index and anisometropic amblyopia.
  
  
  CONCLUSIONS
  Interocular interactions are associated with amblyopia, the degree of anisometropia, and amblyopia treatment outcomes, but these associations are visual function dependent.
authors.affiliation: School of Optometry & Vision Science, University of New South Wales, Sydney, New South Wales, Australia. xinjie.lai@gmail.com
authors.forename: Xin Jie
authors.initials: XJ
authors.lastname: Lai
authors.forename: Jack
authors.initials: J
authors.lastname: Alexander
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.forename: Zhikuan
authors.initials: Z
authors.lastname: Yang
authors.forename: Catherine
authors.initials: C
authors.lastname: Suttle
mesh_terms: D000550:Amblyopia / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D015858:Anisometropia / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D005139:Eyeglasses; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012029:Refraction, Ocular; D012683:Sensory Deprivation; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*