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.