Overall, tear film prednisolone levels were ≥10−9 M (ie, 0.4 ng/mL) in all dogs throughout the 12-h sampling time, a concentration shown to decrease the expression of deleterious cytokines (tumor necrosis factor-α, interleukin-6) and matrix metalloproteinases in a rat model of keratitis.15 Therefore, oral prednisone might have therapeutic benefits in managing corneal inflammation, assuming similar exposure-response between species. The gene discussed is TNF; the disease is keratitis.