Enhancing visual comfort and cognitive performance in VDT Workspaces through task-adaptive screen-desktop luminance contrast optimization

Lighting conditions exert a profound influence on visual comfort, attention, and cognitive performance during visual tasks. In modern offices, visual display terminals (VDTs) have become indispensable as the primary medium for human-computer interaction. However, a mismatch between VDTs and their ambient light environment can impair user experience, necessitating optimized lighting design. Existing standards prioritize screen-background luminance interactions, while the critical role of screen-desktop luminance contrast (SDLC)—a key factor in the central visual field during document reading and typing—remains systematically underexplored despite its growing significance in commercial solutions like ambient lights. To address this gap, we propose the Task-Adaptive Photometric Field, a task-adaptive desktop lighting strategy focusing on optimizing SDLC (3:1–8:1), with synergistic adjustments of correlated color temperature (CCT, 3500–6500 K) and lighting area size (70–110 cm). Through two complementary experiments, we evaluated these parameters’ impact on visual comfort and attention. Experimental results demonstrate that optimized SDLC (5:1–6:1) significantly enhances sustained attention performance (96.4 % accuracy) and reduces visual fatigue by 18.5 %, with moderate CCT (5500 K) and a 90 cm lighting area further improving comfort scores by 4.2 %. Conversely, low contrast (3:1) paired with high CCT (6500 K) improves short-term attention but increases fatigue after 90 min. These findings establish the pivotal role of SDLC in VDT ergonomics, broadening the comfortable luminance range and providing empirical guidelines for adaptive lighting systems that align with task demands, with the potential to enhance user productivity and well-being in intelligent VDT environments.