how does the setting of blindness help in communicating the themes of disintegration of society in a crisis

The novel begins with the apparent first, or index, case of an emerging infectious disease, which causes a form of blindness by causing the infected individual to see only a milky whiteness. The first blind man struggles to get home and then obtain medical assistance. Within hours, all those with whom he has had contact, including the ophthalmologist, are also blind. The doctor contacts the ministry of health and raises the alarm. Within days, the newly blind are forcibly incarcerated in an old mental hospital where they receive no medical care and are completely isolated from the outside world. Over the course of about a week, scores and then hundreds of additional blinded people are incarcerated until the facility is beyond any reasonable capacity. Unbeknownst to the inmates, the disease continues to sweep through the city and then the entire nation until everyone is blind