Designing for calm: exploring the impact of colored light on autonomic regulation and anxiety in patients awaiting cataract surgery

Gilles Guerrier, Eva Hardy, Philomène Robert, Nathalie Junod Ponsard, Patrick Renaud, Pierre-Raphaël Rothschild, Christophe Baillard

Objective To explore whether immersive colored light can be used as a design intervention to reduce preoperative anxiety and modulate autonomic nervous system activity in patients awaiting cataract surgery. Background Preoperative anxiety is common and often underestimated. Environmental factors such as lighting may influence patients' emotional state and physiological stress responses. Integrating light-based strategies into preoperative spaces represents an opportunity for evidence-based design. Methods Thirty patients awaiting cataract surgery were exposed to immersive colored light (blue, green, purple, red, orange, and yellow) for 10 min each in randomized order, with ambient light serving as the control condition. Anxiety was assessed before and after each exposure using a verbal analog scale (VAS). Autonomic regulation was evaluated using heart rate variability (HRV), measured as the root mean square of successive differences (RMSSD) with a wearable sensor. Subjective color perception and color preference were also recorded. Anxiety and autonomic outcomes were analyzed using linear mixed-effects models including lighting condition and color preference as fixed effects and participant as a random intercept. Results Baseline anxiety and RMSSD under ambient light conditions were 5.6 ± 2.1 VAS points and 24.8 ± 9.3 ms, respectively. Linear mixed-effects modeling demonstrated a significant effect of lighting condition on both anxiety and HRV (both p < 0.05). Blue light exposure was associated with significantly lower anxiety scores compared with ambient light [β = −2.87 VAS points; 95% CI (−4.52 to −1.22); p = 0.001] and higher RMSSD values [β = +5.8 ms; 95% CI (2.1 to 9.5); p = 0.003]. Yellow (β = −6.9 ms; p < 0.001) and red light (β = −2.1 ms; p = 0.038) were associated with lower RMSSD values. Color preference was not independently associated with anxiety ( p = 0.37) or RMSSD ( p = 0.46). Anxiety scores were inversely correlated with RMSSD values ( r = −0.42, p = 0.02), whereas no significant correlation was observed with heart rate ( r = 0.18, p = 0.34). Blue light was predominantly perceived as calming, while red and yellow light were most frequently perceived as stimulating. Conclusions This exploratory study suggests that immersive colored light may influence both subjective anxiety and autonomic regulation in patients awaiting cataract surgery. Blue light was associated with reduced anxiety and enhanced parasympathetic activity independently of color preference. These findings support the potential of adaptive lighting design as a non-pharmacological strategy to improve the perioperative patient experience.