Evaluation of a Hirschberg Test-Based Application for Measuring Ocular Alignment and Detecting Strabismus

Area of Science:

• Ophthalmology
• Medical Technology
• Vision Science

Background:

• The Hirschberg test is a valuable clinical tool for strabismus assessment.
• There is a need for accessible strabismus screening tools, particularly in underserved areas.
• Photographic-based applications offer a potential solution for remote or automated assessments.

Purpose of the Study:

• To develop and evaluate a semi-automated Hirschberg test application for strabismus detection and measurement.
• To assess the application's accuracy in identifying the presence and quantifying the magnitude of strabismus.
• To determine the utility of the application as a screening tool in various fixation conditions.

Main Methods:

• A prospective cross-sectional study involving subjects with and without strabismus.
• Development of a semi-automated application utilizing facial photographs for eye detection and Hirschberg reflex analysis.
• Comparison of application measurements with the alternate prism cover test (APCT) for strabismus assessment.

Main Results:

• The application achieved high accuracy (95.14%) in face and eye detection.
• Sensitivity for horizontal strabismus detection was high (92.86%), but specificity was low.
• Bland-Altman analysis revealed significant bias and wide limits of agreement for strabismus measurements, though repeatability showed moderate consistency.

Conclusions:

• The developed semi-automated Hirschberg test application effectively locates facial features and eyes.
• The application demonstrates potential as a screening tool for horizontal strabismus detection.
• Further improvements are needed to enhance the measurement accuracy of strabismus deviations.