Validated facial grimace scales for laboratory animals have transformed pain assessment and analgesic provision in research settings, enabling more timely and appropriate pain management.
The development and adoption of grimace scales has genuinely improved pain management in laboratory animals by making pain visible to observers who previously struggled to recognize it. Animals in pain do not always display obvious behaviors like limping or vocalizing — they often become quiet and inactive. Grimace scales reveal the subtle facial changes that accompany pain even in apparently calm animals, enabling earlier analgesic intervention. Institutions that train animal care staff in grimace scale use consistently report increased analgesic provision and reduced duration of post-procedural pain. The next frontier is automating grimace scale assessment using machine vision systems for continuous pain monitoring.