The role of corneal nerves and neuromodulators in the immune response and healing processes of corneal infections.

The integrity of corneal nerves is essential for maintaining corneal health; however, microbial keratitis caused by Acanthamoeba, fungi, bacteria, and viruses disrupts corneal neuroimmune homeostasis. Advanced imaging of the human cornea and animal models has revealed changes in the corneal subbasal nerve plexus, even in Acanthamoeba and fungal corneal infections. Moreover, corneal nerve regeneration in microbial keratitis relies on neurotrophins, regeneration-associated genes, and nerve guidance molecules. The damage to corneal nerves in microbial keratitis seems to stem from corneal neuroimmune responses or direct pathogen effects. While neuromodulators play a role in corneal healing, the complexity of corneal neuroimmune interactions and the multifactorial nature of infections may complicate establishing definitive therapeutic protocols. Research into the pathological changes and regenerative processes in corneal nerves is ongoing, and it could significantly enhance therapeutic strategies in microbial keratitis, offering hope for better patient outcomes.