Lens power calculation--is it necessary?

In a group of 70 patients from whom myopes were not excluded, 90 per cent resulted in postoperative refraction between -1.75 and +0.75 when the power of implant was calculated using A Scan biometry. Sixty-nine per cent of these patients would have fallen into this refraction bracket had calculation been made purely on clinical grounds. Comparison was made with 569 previous implantations without biometry. In this group life-long myopes above -3.0D had been excluded and the implants available were in 2.0 dioptre increments, choice of power depending on clinical judgement: 77 per cent of these patients fell into the same postoperative refraction bracket.