A major disadvantage of nylon sutures is the need to remove them post-operatively to prevent suture fracture and irritation. Mersilene (polyester) sutures do not hydrolyse or disintegrate and are in theory superior to nylon. Fifty-two consecutive patients were examined an average of 3 years after uncomplicated extracapsular cataract extraction with corneal sections sutured with interrupted 11/0 polyester. It was found that 29% had suture-related problems and required, or had previously undergone, suture removal for reasons other than high astigmatism. The most common problem was a loose stitch with adherent mucus and corneal vascularisation (17% of patients at review). Sixty-six per cent of patients with loose sutures reported discomfort. We would not advocate prophylactic removal, but patients with polyester sutures should be advised to return if they become symptomatic.