Eye Movement Variations in Indoor, Outdoor, and Reading Scenarios and their Implications for Myopia

Purpose: To quantitatively measure eye movement behaviors in indoor, outdoor, and reading scenarios to understand their potential link to myopia. Methods: Forty-one healthy adult subjects freely viewed indoor and outdoor scenes and performed reading activities using virtual reality (VR). Eye movement data were recorded with the built-in eye tracker of the VR headset (HTC Vive Pro Eye). Gaze and fixation data were calculated and reported for eight regions of the visual field. Results: Indoor scenes exhibited a more pronounced downward gaze than outdoor environments. Significant differences (p < 0.05) in gaze and fixation behaviors were observed between reading and other scenarios. In region 8 (peripheral inferior visual field), the median (1st quartile, 3rd quartile) number of gaze points were 816 (463, 1175), 1123 (743, 1497), and 1705 (966, 2382) for outdoor, indoor and reading scenarios, respectively. Similarly, fixation behavior counts were 4 (1, 9), 7 (1, 11), and 39 (22, 54), respectively. Conclusions: Downward gaze and fixation behaviors are more prevalent in reading and indoor environments. Given that downwards eye movements can induce instantaneous axial elongation, our results suggested a potential biomechanical pathway for myopia progression through optic nerve traction and ocular tissue remodeling. This study underscores the need for further research to explore the specific role of eye movement behaviors in the progression of myopia, especially in real-life settings.