Blind Spot Displacement in Binocular Virtual Reality Perimetry: Incidence and Potential Determinants in Healthy Participants.

PURPOSE: To investigate factors associated with unexpected physiologic blind spot displacement (BSD) during visual field testing with a head-mounted virtual reality perimeter (VRP). METHODS: Phase 1 evaluated 65 healthy participants undergoing binocular VRP testing (VisionOne system) to determine BSD incidence and compare baseline refractive error between BSD and non-BSD groups. Phase 2 compared refractive status, horizontal phoria (Maddox Wing test), and ocular dominance assessed with real-world (RW) and Unity3D VR-adapted Dolman paradigms in 14 BSD and 17 non-BSD participants. Exploratory OCT-based disc-foveal angle (DFA) characterization was available in nine BSD cases. RESULTS: BSD was identified in 14 participants (19 eyes), yielding an incidence of 21.5% (14/65). Participants with BSD had significantly greater myopia than controls (-2.68 ± 2.45 D vs -0.58 ± 1.67 D; P = 0.012), whereas horizontal phoria did not differ significantly (5.29 ± 3.47 Δ vs 3.71 ± 4.19 Δ; P = 0.261). Clinically significant anisometropia (≥1.0 D) was present in three BSD participants, two with binocular BSD. BSD occurred most often in the non-dominant eye (50.0%, 7/14). Dominance-assignment instability or transition patterns were observed in 28.6% (4/14) of BSD cases across RW and VR assessments. In nine BSD cases undergoing exploratory OCT, DFA values were reviewed descriptively in relation to BSD direction. CONCLUSION: BSD was observed during binocular immersive VRP and was associated with greater myopic refractive error. Ocular dominance behavior and OCT-based DFA characterization may provide exploratory context for its spatial patterns. Recognition of BSD may help improve calibration, fixation monitoring, and interpretation of apparent scotoma patterns in VRP.