Immune Privilege of Eyes

Your eyes have their own immune system, so if they get infected, it's up to them to handle it. Your eyes are "immune privileged," meaning the rest of the body’s immune system has no knowledge of their existence. If this immune system were to suddenly become aware of the eyes, it may treat them as a threat and try to neutralize them, potentially leading to blindness. This is why severe eye trauma to even one eye can be particularly dangerous, as it can expose the immune system to antigens in the eye and blind both of them.