Eye-Tracking Based Device for Measurement of Both Manifest and Latent Eye Deviations in Adults and Children
Tamara Wygnanski-Jaffe, MD; Abraham Spierer, MD; Michael Belkin, MD; Dan Oz; Oren Yehezkel, OD
Goldschleger Eye Institute and Novasight Ltd.
Tel Hashomer, Airport City, Israel
Introduction: The current gold standard test for eye deviation measurement is the manual prism cover test. This test is at times challenging and limited by the level of cooperation and the examiner’s skill. Cover tests are time-consuming and cumbersome and studies have shown high inter-examiner variability 1. Moreover, the angle of strabismus itself may vary and the current tests do not allow quick multiple testing of the same patient.
Methods: We conducted a clinical trial to evaluate the accuracy and repeatability of the Eyeswift, a novel eye deviation angle measurement method using an automatic system based on eye tracking, and compared it to the prism cover tests. A group of 24 adult subjects with eye deviations, were tested by both the automatic and cover tests in a masked fashion.
Results: A correlation of 89% was found between the automatic test and the golden standard of prism cover tests. The repeatability of the automated test was twice as high as that of the manual test (mean STD 1.35 vs. 0.71 respectively (P<0.005 paired t-test)). The average deviation measured by the automatic test was 13.5±1.5 (SD) and comparable to the cover test results of 14.2±1.3 (SD).
Discussion: The automated measurement is an accurate reproducible system. The system also reduces chair time significantly and has the potential of becoming a standard of care.
Conclusion: The system performs accurate automated orthoptic measurements. This can increase the work efficiency of ophthalmologists, in addition it may aid in prescription of prisms, monitor orthoptic therapy and provide pre and post op measurements.
References: 1. De Jongh, E., et al. ‘Inter-examiner variability and agreement of the alternate prism cover test (APCT) measurements of strabismus performed by 4 examiners.’ Strabismus 22.4 (2014): 158-166.