Whilst GAE has only been reported in immunocompromised individuals, keratitis may affect those who are healthy and immunocompetent. All normal individuals will mount a humoural immune response to the infection, which is effective in vascularised regions of the body. However, in the immunoprivileged cornea, the normal oxidative destruction of the organism by neutrophils is weakened as it relies on antibodies marking the organism prior to destruction.
The pathogenesis of the keratitic process has been classified into three stages: (1) epithelial adhesion and desquamation; (2) stromal invasion; (3) neuritis.