Following up The Constant Gardener, an intellectually-stimulating thriller based on a John le Carre novel, with Blindness, a post-apocalyptic tale of a world in which people (as the title might suggest) turn suddenly blind, would seem like an odd change in tone for director Fernando Meirelles. Remember however his break into English-language film was with 2002's similarly diverse effort City of God - If Blindness confirms anything, it's that this is a director not content to repeat himself.

Mark Ruffalo is an eye doctor who encounters a patient with a strange condition - he can see nothing but bright, white light, even though there's nothing physically wrong with his eyes. It's not long before the doctor finds himself unable to see and very quickly a chain of people around him begin to go blind. With the government keen on containment, the victims are quarantined in an old, decrepit hospital and cut off completely from the outside world. Things soon start to deteriorate as the blind struggle to live in the unfamiliar environment.

The exception is Julianne Moore as the doctor's wife. She's immune to the affliction and finds herself playing nursemaid to her husband from within the facility. But as the victims start forming packs and becoming more violent, standards of human decency slip and life becomes harder within the group.

Like most post-apocalyptic movies, Blindness delivers a rabid, dirty, oversaturated universe and then lets a group of morally bankrupt characters run amok. The premise is a fascinating one, but Meirelles never pulls back and lets us see the carnage wrecked by the freak illness on the wider world. As the film unspools because it becomes clear that we're going to spend more time with the main players than with the universe as a whole. Characters come and go but we stay with a core group and actually never learn much about them beyond their needs in the moment of any particular scene. Even their names are generic - the Doctor, the Doctor's Wife, the First Blind Man - just as the city they inhabit is unidentifiable but probably American. You spend most of the film in the company of a set of disconcertingly vague archetypes - characters with not enough, well, character, to make us care about them.

Meirelles certainly goes to great lengths to nightmarish vision of the future, though his world does kind of resemble a zombified version of Children of Men, as characters wander aimlessly through grey corridors with their arms stretched out in front of them. Touches of visual genius do remain, particularly when the director is exploring the idea of blindness - at one point the reflection of a white sky on a car window inhibits our vision of the scene, while at another a boy shuffles down a corridor before bumping into a table that appears as soon as he hits it - though these fantastic touches do leave you yearning for more. Indeed at certain points you almost forget the characters are blind.

Ultimately, Blindness is a brave attempt from this ever-versatile director at creating an intelligent, original sci-fi thriller that, sadly, never quite comes together. There is entertainment to be had in spite of its flaws - though as Danny Glover's philosophical narration starts to kick in you begin to wish the film provided the sort of impact his words allude to - and strong performances from Julianne Moore, Mark Ruffalo and Gael Garcia Bernal do as much for the characterisation as the script allows. But, as the credits roll, frustration and indeed bafflement linger in the mind, as you wonder how a project with such a strong central conceit and fantastic array of talent failed to deliver anything more fascinating than a visually arresting, but shallow and somewhat derivative entry in the post-apocalyptic sub-genre.