I pride myself on being able to watch just about anything on television - hell, I even sat through a whole episode of Next of Kin once. But eye surgery defeats my powers of unblinking vision. I don't know whether it is the snail horn sensitivity of the eyeball or the fact that it is the one medical procedure in which patients can't be told to "close your eyes 'till it's all over", but it strikes me as an unwatchable emblem of wincing vulnerability. Even so, I tried quite hard during Health Alert (C4), a television critic with a cushion in front of his face not being entirely qualified for the task in hand. I think I'm now suffering from a case of documentary-induced astigmatism, the battle between the professional duty to keep my eyes open and the private instinct to squeeze them tight shut having left me with an appalling squint.

Health Alert's title sequence includes a repeated shot of dice being rolled over an image of an operating room, which suggests that it hasn't been sponsored by the BMA in an attempt to drum up more business. Instead, the series marks an attempt to fight back against Watchdog's expanding colonisation of consumer affairs (their spin-off Healthcheck programme runs on BBC1 earlier in the evening), and this opening episode examined the recent boom in laser eye surgery, a procedure which makes very large promises for a permanent cure. ("A trip to the optician could very soon become a thing of the past," said Shahnaz Pakravan in a way that somehow managed to combine technological optimism and the imminent arrival of a large "but".) Those who have undergone the operation - including many of the telesales people employed in one private clinic - talk of a transformation in the way they see the world which goes far beyond the merely optical.

"PRK will not only change your lifestyle - it will change your personality... giving you confidence to do things which you previously might not of thought of doing," said one salesman, beaming like a Mormon. Oddly, though, he was still wearing glasses himself, a rather undermining detail which was to become a recurrent theme of the film. At a conference of eye experts convened to discuss the new laser treatments, not one of those attending had undergone surgery - despite the fact that many of them wore glasses and performed the operation on their patients. Others were quite explicit about the risks: "If you make a mistake of a few microns, it could be devastating," explained one eye surgeon. Her address to the conference included a comparison between laser surgery and getting on a roller-coaster "because you know you're going to be horrified at some point". As she was performing these procedures on others, it would have been nice to have the obvious question asked here - "Why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?" - but Health Alert took the discrepancy as a warning light rather than an ethical scandal.

Their scepticism was chiefly reserved for the low-cost clinics who aim to keep the treatment price down by sheer volume of turnover. One of these had been set up by a man whose other business was manufacturing jewellery for the Argos catalogue, not perhaps the most reassuring pedigree in the world. He was one of the optically born-again himself, having started what he hopes will be a chain of laser surgery clinics after undergoing surgery on his own eyes. But Health Alert poured some cold water on his vision of miraculous remedy, pointing out that as many as 5 per cent of laser surgery patients may be left with lasting problems - halos around lights, permanent hazing, distortion and shadowy ghosting of objects. The last word was upbeat - a satisfied customer who declared, in revival-meeting style, that she was going to throw away her glasses for ever - but the odds of seeing the world as if it was being transmitted by Channel 5, seemed to me far too high to be tempting.