Topical rewetting restores the autoimmune-damaged corneal stroma

Corneal wetting is the most common treatment for dry eye disease and is generally considered palliative. Here, we challenge this view by demonstrating that rewetting the desiccated cornea of an aqueous-deficient mouse model with the simplest rewetting agent, phosphate-buffered saline (PBS), is sufficient to restore the severely disrupted collagen-rich stromal architecture required for transparency. Using transmission electron microscopy, we show substantial recovery of stromal organization, including a marked reduction in interfibrillar spacing consistent with resolution of stromal edema, following rewetting. Single-cell transcriptomic analyses further reveal that stromal keratocytes transition from an inflammatory state to a reparative-like phenotype in response to rewetting alone, demonstrating keratocyte plasticity and the potential regenerative function of rewetting. This reparative shift is mediated, in part, by dampening of IL-1β associated MAPK signaling. Together, these findings uncover an unexpected regenerative capacity of corneal rewetting and redefine its therapeutic impact in dry eye disease.