Development and Clinical Validation of a Digital Eye-Tracking-Based Cover Test for Ocular Misalignment

Area of Science:

• Ophthalmology and Vision Science
• Medical Technology and Instrumentation
• Diagnostic Accuracy Studies

Background:

• The cover test is a fundamental clinical assessment for detecting ocular misalignment (strabismus).
• Traditional cover tests rely on subjective observation, introducing potential variability.
• There is a need for objective, portable, and accurate tools to quantify ocular deviations.

Purpose of the Study:

• To develop and validate the DIVE Cover Test (DCT), a portable, eye-tracking-based digital cover test.
• To assess the DCT's diagnostic accuracy, agreement with the classic cover test (CCT), and repeatability.
• To evaluate performance across different cover test phases (cover-uncover test [CUT] and alternate cover test [ACT]) and ocular axes (horizontal and vertical).

Main Methods:

• A prospective clinical validation study involving 68 participants (3-74 years) with and without strabismus.
• Participants underwent repeated DCT and CCT examinations by experienced clinicians at near distance.
• Diagnostic performance (sensitivity/specificity), intermethod agreement (Bland-Altman, ICCs, Pearson correlation), and test-retest repeatability were analyzed.

Main Results:

• The DCT demonstrated high diagnostic accuracy: 85% sensitivity and 98% specificity in CUT; 92% sensitivity and 87% specificity in ACT.
• Strong agreement was observed between DCT and CCT, particularly for horizontal deviations during ACT (ICC=0.96).
• Excellent DCT test-retest repeatability (ICC ≥0.93) and narrow limits of agreement (±3.8 to ±4.6 PD) were achieved across all conditions.

Conclusions:

• The DIVE Cover Test (DCT) is a highly accurate and repeatable tool for quantifying ocular misalignment.
• It shows strong agreement with the established classic cover test (CCT), supporting its clinical utility.
• The DCT offers a practical, portable, and objective alternative for strabismus evaluation in clinical settings.