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Updated: May 21, 2026
Using an Automated Hirschberg Test App to Evaluate Ocular Alignment
Published on: March 24, 2020
A novel apparatus for interocular interaction evaluation in children with and without anisometropic amblyopia
Xin Jie Angela Lai1, Jack Alexander, Ming Guang He
1School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia. xinjie.lai@gmail.com
Insights
The trial frame apparatus (TFA) is a feasible tool for evaluating visual interactions in children, showing better engagement and shorter training times compared to goggles. This system is particularly useful for studies involving amblyopic children.
Area of Science:
- Ophthalmology
- Pediatric Vision
- Visual Neuroscience
Background:
- Dichoptic visual stimulation is crucial for understanding visual perception.
- Existing methods like shutter goggles and mirror systems have limitations for pediatric use.
- A novel trial frame-based system (TFA) was developed to assess visual interactions in children.
Purpose of the Study:
- To investigate the feasibility and efficacy of a trial frame apparatus (TFA) for evaluating visual interactions in children.
- To compare the TFA with traditional shutter goggles in terms of visual function measurement and subject engagement.
- To assess the utility of the TFA for research in pediatric amblyopia.
Main Methods:
- Low contrast acuity, contrast sensitivity, and alignment sensitivity were measured in 38 children (aged 5-11) using the TFA and goggles.
- The 'interaction index' was calculated based on visual functions under full and partial dominant eye occlusion.
- Agreement between TFA and goggles was assessed using Bland-Altman and t-tests; training duration, breaks, and willingness to participate were recorded.
Main Results:
- The TFA demonstrated acceptable agreement with goggles for most visual functions and interaction measures (p > 0.05).
- Contrast sensitivity training was significantly shorter with the TFA (p ≤ 0.001), and fewer breaks were needed during testing (p < 0.045).
- Children showed greater willingness to participate in further experiments using the TFA compared to goggles (p = 0.025).
Conclusions:
- The trial frame apparatus (TFA) is a viable and user-friendly alternative to goggles for assessing visual functions and interactions in children.
- The TFA offers advantages in reduced training time and improved subject compliance, especially for pediatric populations.
- This system holds promise for future research, particularly in the field of amblyopia studies in children.
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).
Conclusion:
The TFA may be a useful tool in studies of interactions in amblyopes, particularly in studies of children's vision.
