title: Quantitative measurement of interocular suppression in anisometropic amblyopia: a case-control study.
abstract: OBJECTIVE
  The aims of this study were to assess (1) the relationship between interocular suppression and visual function in patients with anisometropic amblyopia, (2) whether suppression can be simulated in matched controls using monocular defocus or neutral density filters, (3) the effects of spectacle or rigid gas-permeable contact lens correction on suppression in patients with anisometropic amblyopia, and (4) the relationship between interocular suppression and outcomes of occlusion therapy.
  
  
  METHODS
  Case-control study (aims 1-3) and cohort study (aim 4).
  
  
  METHODS
  Forty-five participants with anisometropic amblyopia and 45 matched controls (mean age, 8.8 years for both groups).
  
  
  METHODS
  Interocular suppression was assessed using Bagolini striated lenses, neutral density filters, and an objective psychophysical technique that measures the amount of contrast imbalance between the 2 eyes that is required to overcome suppression (dichoptic motion coherence thresholds). Visual acuity was assessed using a logarithm minimum angle of resolution tumbling E chart and stereopsis using the Randot preschool test.
  
  
  METHODS
  Interocular suppression assessed using dichoptic motion coherence thresholds.
  
  
  RESULTS
  Patients exhibited significantly stronger suppression than controls, and stronger suppression was correlated significantly with poorer visual acuity in amblyopic eyes. Reducing monocular acuity in controls to match that of cases using neutral density filters (luminance reduction) resulted in levels of interocular suppression comparable with that in patients. This was not the case for monocular defocus (optical blur). Rigid gas-permeable contact lens correction resulted in less suppression than spectacle correction, and stronger suppression was associated with poorer outcomes after occlusion therapy.
  
  
  CONCLUSIONS
  Interocular suppression plays a key role in the visual deficits associated with anisometropic amblyopia and can be simulated in controls by inducing a luminance difference between the eyes. Accurate quantification of suppression using the dichoptic motion coherence threshold technique may provide useful information for the management and treatment of anisometropic amblyopia.
  
  
  BACKGROUND
  Proprietary or commercial disclosure may be found after the references.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Jinrong
authors.initials: J
authors.lastname: Li
authors.forename: Robert F
authors.initials: RF
authors.lastname: Hess
authors.forename: Lily Y L
authors.initials: LY
authors.lastname: Chan
authors.forename: Daming
authors.initials: D
authors.lastname: Deng
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Xiang
authors.initials: X
authors.lastname: Chen
authors.forename: Minbin
authors.initials: M
authors.lastname: Yu
authors.forename: Benjamin
authors.initials: B
authors.lastname: Thompson
mesh_terms: D000550:Amblyopia / Q000503:physiopathology* / Q000628:therapy*; D016022:Case-Control Studies; D002648:Child; D015331:Cohort Studies; D003261:Contact Lenses; D003867:Depth Perception / Q000502:physiology; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D012683:Sensory Deprivation; D016896:Treatment Outcome; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology