title: Design and validation of a method for evaluation of interocular interaction.
abstract: OBJECTIVE
  To design a simple viewing system allowing dichoptic masking, and to validate this system in adults and children with normal vision.
  
  
  METHODS
  A Trial Frame Apparatus (TFA) was designed to evaluate interocular interaction. This device consists of a trial frame, a 1 mm pinhole in front of the tested eye and a full or partial occluder in front of the non-tested eye. The difference in visual function in one eye between the full- and partial-occlusion conditions was termed the Interaction Index. In experiment 1, low-contrast acuity was measured in six adults using five types of partial occluder. Interaction Index was compared between these five, and the occluder showing the highest Index was used in experiment 2. In experiment 2, low-contrast acuity, contrast sensitivity, and alignment sensitivity were measured in the non-dominant eye of 45 subjects (15 older adults, 15 young adults, and 15 children), using the TFA and an existing well-validated device (shutter goggles) with full and partial occlusion of the dominant eye. These measurements were repeated on 11 subjects of each group using TFA in the partial-occlusion condition only. Repeatability of visual function measurements using TFA was assessed using the Bland-Altman method and agreement between TFA and goggles in terms of visual functions and interactions was assessed using the Bland-Altman method and t-test.
  
  
  RESULTS
  In all three subject groups, the TFA showed a high level of repeatability in all visual function measurements. Contrast sensitivity was significantly poorer when measured using TFA than using goggles (p < 0.05). However, Interaction Index of all three visual functions showed acceptable agreement between TFA and goggles (p > 0.05).
  
  
  CONCLUSIONS
  The TFA may provide an acceptable method for the study of some forms of dichoptic masking in populations where more complex devices (e.g., shutter goggles) cannot be used.
authors.affiliation: The School of Optometry and Vision Science, The University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Xin Jie Angela
authors.initials: XJ
authors.lastname: Lai
authors.forename: Jack
authors.initials: J
authors.lastname: Alexander
authors.forename: Arthur
authors.initials: A
authors.lastname: Ho
authors.forename: Zhikuan
authors.initials: Z
authors.lastname: Yang
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.forename: Catherine
authors.initials: C
authors.lastname: Suttle
mesh_terms: D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D015350:Contrast Sensitivity; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D058453:Emmetropia / Q000502:physiology*; D004867:Equipment Design; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015348:Vision, Binocular; D055815:Young Adult