Quantifying Eye Alignment in Orbital Fracture Patients: The Digital Hess Screen

Background: Quantifying diplopia to determine management and track outcomes for orbital fracture patients is vital for standardization between visits, physicians, and coordination among the multiple specialties that manage these patients. However, standardization is challenging, as diplopia is often reported subjectively. This study sought to describe the utility of the digital Hess screen in patients with orbital fractures compared with a control group. Materials and Methods: A prospective pilot study was designed in which adult patients who presented with orbital fractures between November 2017 and January 2019 without prior history of orbital pathology were recruited. Subjects underwent digital Hess screen testing, in which they wore anaglyph glasses and aligned targets on a computer screen to quantify static eye alignment. The degree of any eye misalignment was analyzed and compared with controls. Results: Ninety-one patients and 35 controls were enrolled. All participants were able to complete the digital Hess screen. Average cumulative deviation score of orbital fracture patients within 1 month of injury was 0.65°, compared with 0.28° in controls. This was a statistically significant difference (p < 0.01, 95% confidence interval -0.18 to 0.18). Conclusion: The Hess screen has been used to quantify phoria as a correlate of eye alignment and diplopia, but older versions were cumbersome and difficult to analyze. This study is the first to report on using the digital Hess screen to quantify phoria in orbital fracture patients and provides a more concise and standardized means to track clinical and surgical outcomes of eye alignment.