IL12B and keratitis: The dominant SNP rs3212227 in IL12B has been associated with a lower risk of having sterile keratitis compared with controls (with sterile keratitis being defined as no positive corneal culture or, where culture was not performed, a corneal infiltrate and overlying epithelial defect outside of the central 4 mm of the cornea, no uveitis, and no significant pain) [64].