There is something about an eye operation that makes the patient feel peculiarly vulnerable. When I entered the cataract ward at the Sussex Eye Hospital last month, I was aware that cataract operations had become as routine as an operation is likely to get, and that the consultant who was scheduled to operate on me was one of the best in the business. Statistically, only one in a thousand such operations go wrong, but the odds against didn't seem nearly as great as I would have liked.

There were already several other patients in the ward, waiting to be briefed in detail about was going to happen to them. The oldest was 94, and seemed entirely calm.

Shortly before I was wheeled into the operating theatre, a nurse asked if I would like my hand held during the operation; I thought she was joking. "Not by me," she added quickly, "we have official handholders authorised to sit with you during the operation. They're all volunteers."

So it was that I met Kit Keay, a 76-year-old retired book-keeper who looked a dozen years younger. She was wearing green scrubs and an encouraging smile.

"You have to be absolutely still during the operation," she told me, "so you won't be able to talk to anyone, because speaking causes your eyes to move. Still, I can chat to you if you like, just to take your mind off things, though you won't feel anything and it'll all be over before you realise it." She put her hand in mine. "If you start to feel uncomfortable, just press my hand twice, and I'll tell the surgeon."

The effect of holding hands proved benevolent therapy, and I was grateful for it, like my fellow patients. Because of the extremely delicate nature of cataract operations, if there were no volunteers to do it the handholding would have to be done by nurses, as it is not only a gesture of kindness but also an essential part of the operation.

"Cataract operations are the only ones where handholders are essential, as moving your head even fractionally is not a good idea," Yvonne Marlow, who runs the volunteers' group, told me. "I don't know whether other hospital trusts use volunteers like us, but we'd be lost without them, as the cost of taking a skilled nurse off her other duties to do it each time would be enormous." Sussex's handholders are all female, some as young as 20.

Marlow doesn't know exactly when the practice of allowing volunteers to work as handholders in operating theatres started, but she thinks it was probably contemporaneous with the evolution of the modern cataract operation, when the actual time a patient has to remain absolutely still from beginning to end of proceedings has been reduced from hours to a manageable 20 minutes.

What medical science has not yet managed to reduce is the patient's apprehension; the literal helping hand offered by hospital volunteers serves as a metaphor become reality, a genuine expression of human kindness which is beyond officialdom and the many troubles that beset the NHS, a fleeting contact whose power to comfort has the same effect between two strangers as it does between lovers.