Indications for the multizone bifocal implant.

A significant improvement in unaided visual standards may be achieved by switching from a monofocal to a 3M diffractive bifocal implant; however, this results in a loss of clarity, particularly for small print, in some patients. In a prospective study of 55 bifocal eyes and 55 monofocal eyes, best-case analysis showed 81% of 52 eyes with bifocal implants could read J5 with their distance correction compared with 21% of the control eyes and 56% could read J2 with the distance correction compared with 2% of the control eyes; 75% of bifocal eyes could read both 20/40 and J3 without any aid compared with 33% of the control eyes. The 3.5 diopter focus difference in the bifocal lens produced commendable results, with 52% requiring no spectacle reading addition. However, the fact that 17% of bifocal eyes could not read J2 highlights certain drawbacks that are relevant to indications for use.