Maybe it's just because I'm in a pissy mood, but I'm not buying this story.
For one thing, Saramago is rather particular about numbers and distances and yet I can't quite grasp how two wings of three wards each, each holding maybe twenty people or so comes out to three hundred people.
Or, the fact that when the last large load of a couple hundred people were moved in, the not-yet blind were of course prevailed upon to give up space and yet we don't really have any but the doctor's wife and possibly a gunman who still can see.
Or the mixup in food distribution, the lack of any medical supplies given to the people, the too-soon attitude of the outside world to have given up on the afflicted, the seeming lack of affiliation as new people are brought in—knowing full well that it appears to spread by some form of contagion, the willingness to give all valuables to one man with a gun when by sound alone they could have overcome him, the lack of the doctor's attempt to find out why his wife can still see, the layout of the courtyard where it seemed to be enclosed by the wings and yet the doctor's wife is out there one night and sees the soldiers at the gate (this I could well be misreading), and a few other things that generally do not quite add up to a picture that is well-painted by the author.
There is also no real interaction between the characters, and this, with Saramago's choice to not quote dialogue takes one out of the story, much like watching a play. There may be a good reason for all this in the scheme of things, as Saramago would be hard pressed to quote dialogue when the characters remain nameless but are referred to instead by "the first blind man," "the doctor's wife," "the man with the black eye patch," etc.