What is the main conflict in Blindness by Jose Saramago?

A man suddenly goes blind for no apparent reason. As a doctor tries to assign an etiology, the condition begins to spread rapidly as if caused by a pathogen. Within days, there are hundreds of newly blind people and within a few months, the entire nation has gone blind. The government responds initially by creating large quarantine areas where infected persons are forcibly held without recourse to medical care or outside assistance. As the disease sweeps the nation, first social services then law enforcement completely fail, leaving the country in a state of chaos as the strong begin to prey upon the weak. Numerous crimes and outrages are perpetrated even as hundreds of thousands begin to starve and die. One small group of blind people coalesces around the leadership of a woman who - apparently uniquely - does not go blind. She cares for her new friends for many days until the disease begins to run its course and the afflicted begin to regain their sight, only to discover a world full of filthiness and destruction.