What metaphors are used in Blindness by Jose Saramago?

In order to impart to his readers the seriousness of the epidemic (blindness), the author reveals how an ophthalmologist— whose job is to cure visual impairments— himself falls victim to the contagious disease. What Saramago is also metaphorically suggesting is that, in the long run, even the few enlightened people who are capable of diagnosing social diseases are capable of ignoring others' needs. What is worse, they may also, reluctantly and fully aware of the dire consequences, act just as reprehensibly as the unenlightened.