Vergence is widely used as a proxy for depth perception and spatial attention in immersive and real-world eye-tracking studies. In this paper, we investigate how pupil size artefacts affect vergence estimates during real physical depth viewing with a head-mounted eye tracker. Using a beamsplitter setup with physically near and far targets, we elicited controlled convergent and divergent eye movements under static, luminance-modulated, and blockwise fixation conditions. Near and far targets were reliably separable in vergence angle across participants. However, pupil-vergence coupling varied substantially across individuals and conditions. Static illumination produced large inter-participant variability, while luminance modulation reduced this spread, yielding more clustered estimates. Blockwise and audio-cued recordings further showed that pupil-vergence coupling persists even without visual depth onsets. These results suggest that pupil size fluctuations can systematically influence vergence estimates, and that controlled viewing conditions can reduce--but not eliminate--this effect.

翻译：辐辏在沉浸式和真实世界眼动追踪研究中广泛用作深度感知和空间注意力的代理指标。本文研究在使用头戴式眼动追踪器观测真实物理深度时，瞳孔尺寸伪迹如何影响辐辏估计。通过采用分束器装置设置物理上的近目标与远目标，我们在静态、亮度调制及分块注视条件下诱发了受控的聚散性眼动。不同被试可基于辐辏角度可靠区分近远目标。然而，瞳孔-辐辏耦合在不同个体和条件间存在显著差异：静态照明导致较大个体间变异性，而亮度调制则缩小了该分散度，使估计值更趋聚类。分块和音频提示记录进一步表明，即使没有视觉深度起始信号，瞳孔-辐辏耦合仍然存在。这些结果表明瞳孔尺寸的波动可能系统性地影响辐辏估计，且受控观测条件可减少——但无法消除——此类影响。