A new meta-analysis has found that placebo and vehicle responses in dry eye disease (DED) trials are more substantial than previously recognized, with implications for how future studies should be designed.
The review included 49 clinical trials involving 3,529 participants assigned to placebo or vehicle groups. Results showed meaningful improvements in both symptoms and signs of DED, including the Ocular Surface Disease Index (OSDI), tear breakup time (TBUT), and corneal and conjunctival staining. Notably, OSDI scores improved by an average of more than 8 points, while TBUT and staining measures also showed significant gains.
Further analysis found that women and patients with more severe baseline symptoms were more likely to experience stronger placebo or vehicle responses in symptom scores. However, no specific predictors were identified for improvements in clinical signs.
Investigators emphasized that these findings highlight the need to account for placebo and vehicle effects when designing and interpreting DED trials.
Reference
Huang A, Zhang A, Lee D, et al. Placebo or vehicle effects on dry eye signs and symptoms in randomized controlled trials: A systematic review and meta-analysis. Surv Ophthalmol. 2025;S0039-6257(25)00146-8. doi: 10.1016/j.survophthal.2025.08.014. Epub ahead of print. PMID: 40882708.
Related Content
