Pupil symmetry and Swinging Light Test Performed with VR Headset for Detection of Anisocoria and Relative Afferent Pupillary Defect

Pupil examination is a routine examination of patients presenting with ophthalmological or neurological symptoms. Our purpose was to determine the sensitivity of pupillometry using HP Reverb G2 Omnicept virtual reality (VR) headset for detecting anisocoria and relative afferent pupillary defect (RAPD).

Methods

Twenty-nine patients were included; Group I with asymmetric optic neuropathy (N=21) and Group II with suspected pathological anisocoria (N=8); alongside 19 controls. VR pupillometry consisted of Pupil symmetry test and Swinging light test. Pathological thresholds were established using upper limits of controls. Results were compared with routine pupil exam. Correlations with functional ophthalmological test results were analyzed.

Results

RAPD was detected in 16/21 Group 1 patients using both VR pupillometry and standard exam. Remaining 5 had relative afferent pupillary asymmetry (RAPA) within the control range (0.1–0.2 mm). Significant correlation was found between RAPA/RAPD and inter-eye difference in visual acuity and visual field defect (MD) (R=0.58 and 0.68, p<0.01). All patients with >5,8 dB inter-eye MD difference had RAPD. In Group II, pathological anisocoria (>0.8 mm) was detected using VR pupillometry and 1/8 on standard exam. Qualitative differences in pupillary constriction were observed. In control group anisocoria (0.4–0.8 mm) was detected in 37% (7/19); in all greater in the dark (mean 0.2 mm).

Conclusion

In comparison to conventional exam VR pupillometry matched detection rate of RAPD and surpassed detection rate of pathological anisocoria. Longitudinal data on pupillary constriction characteristics could significantly contribute to patient diagnosis and monitoring in clinical studies as well as understanding physiological variability.