A novel apparatus for interocular interaction evaluation in children with and without anisometropic amblyopia.
BACKGROUND
Dichoptic visual stimulation may be achieved using shutter goggles and mirror systems. These methods vary in their feasibility for use in children. This study aims to investigate the feasibility of use of a simple trial frame-based system to evaluate interactions in children.


METHODS
Low contrast acuity, contrast sensitivity and alignment sensitivity were measured in the non-dominant eye of 10 normally-sighted children, 14 anisometropic children without amblyopia and 14 anisometropic amblyopic children (aged 5-11 years) using goggles and a trial frame apparatus (TFA). The dominant eye was either fully or partially occluded. The difference in visual functions in the non-dominant eye between the full and partial occlusion conditions was termed the 'interaction index'. Agreement between the TFA and goggles in terms of visual functions and interactions was assessed in anisometropic children with and without amblyopia using the Bland-Altman method and t-test. Training sessions allowed subjects to become accustomed to the systems and tasks. The duration of training, the number of breaks requested by subjects and their willingness to attend further experiments were recorded in 10 subjects from each group and were compared between groups and between systems.


RESULTS
Both Bland-Altman and t-test methods indicated acceptable agreement between the TFA and goggles in visual function and interaction measures (p > 0.05), except for contrast sensitivity measured in anisometropic children without amblyopia (p = 0.042). For all subject groups, contrast sensitivity training was significantly longer using goggles than using the TFA (p ≤ 0.001). Significantly more breaks were requested in acuity and contrast sensitivity testing, when goggles were used than when the TFA was used (p < 0.045). Anisometropic children without amblyopia showed a significantly greater willingness to attend more experiments using the TFA than using goggles (p = 0.025).


CONCLUSIONS
The TFA may be a useful tool in studies of interactions in amblyopes, particularly in studies of children's vision.
School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia. xinjie.lai@gmail.com
Xin Jie Angela
XJ
Lai
Jack
J
Alexander
Ming Guang
MG
He
Zhi Kuan
ZK
Yang
Catherine
C
Suttle
D000550:Amblyopia / Q000503:physiopathology*; D015858:Anisometropia / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005135:Eye Protective Devices; D005260:Female; D006801:Humans; D008297:Male; D014792:Visual Acuity