The issue of BVM has re-emerged with the widespread adoption of virtual reality (VR) and augmented reality (AR) displays; however, the results from the previous studies cannot be easily translated to AR/VR setups. Such devices exhibit two opposing issues related to BVM and discomfort. On one hand, adaptation of the eye posture can occur relatively quickly (
Kim, Vicci, Granger-Donetti, & Alvarez, 2011) and is expected to mitigate symptoms of visual discomfort for longer exposures. On the other hand, visual discomfort is known to increase cumulatively over time during continuous exposure (
Collins, Brown, Bowman, & Caird, 1991). In VR setups, the issue of BVM is only seldom considered (e.g., see review in
Souchet, Lourdeaux, Pagani, & Rebenitsch, 2023), and it is primarily related to individual interpupillary distances and the distance between the optical elements (
Hibbard, van Dam, & Scarfe, 2020). Likewise, subsequent works in AR are mainly based on guidelines from
Self (1986) and lack further investigation (e.g., see review in
Cakmakci & Rolland, 2006). To gain a better understanding of the effects of BVM in AR setups, it is important to investigate how the visual system responds to misalignments. Eye movements are well adapted to the natural environment statistics (
Gibaldi & Banks, 2019;
Aizenman et al., 2023) and are able to quickly adapt to sudden changes in the environment (
Kim et al., 2011), particularly to vertical misalignments (
Schor & McCandless, 1995). The level of vertical disparity that can be tolerated goes well above the limits suggested by the various studies, approximately 2.5° for small stimuli (
Bharadwaj et al., 2007) and up to 7° for large stimuli (
Kertesz, 1981). In these studies, the stimulus was shown at the central portion of the field of view, and generally the experiments were performed in a dark room. As a result, these configurations resembled the visual stimulation of a VR setup, where any vertical misalignment is coherent over the entire field of view.