Aims: To evaluate the functional effect of bilateral implantation of two different multifocal intraocular lenses (IOL) compared with the standard monofocal IOL.
Methods: Sixty-nine patients were recruited into a prospective, double-masked, randomised, controlled trial at a single hospital in the United Kingdom. Sixty completed follow-up; 16 implanted with monofocal IOLs, 29 with AMO 'ARRAY' multifocal IOLs and 15 with Storz 'TRUEVISTA' bifocal IOLs. Phacoemulsification and IOL implantation was performed to a standardised technique in both eyes within a 2-month period. The main outcome measures were distance and near visual acuity, depth of field and validated assessment of subjective function (TyPE questionnaire).
Results: naided distance acuity was good, and equivalent across the three groups. Corrected distance acuity was significantly lower in the bifocal group. Patients with multifocal and bifocal IOLs could read smaller absolute print size than those in the monofocal group (P = 0.05), but at a closer reading distance such that mean unaided near acuity was equal in the three groups. Corrected near acuity was significantly higher in the monofocal control group (P < 0.05). Depth of field was increased in multifocal (P = 0.06) and bifocal (P = 0.004) groups. Overall visual satisfaction was equal in the three groups, while near visual satisfaction was higher in the multifocal group than the monofocal (P = 0.04). Spectacle independence was not seen in the monofocal group, but was achieved in 28% of multifocal IOL patients and 33% of bifocal patients (P < 0.001). Adverse symptoms such as glare and haloes were significantly more bothersome with multifocal (not bifocal) IOLs than monofocals (P = 0.01).
Conclusions: Multifocal and bifocal IOLs improved unaided near vision performance, with around one in three patients becoming spectacle-independent. The main adverse effect was an increased incidence of subjective glare and haloes in the multifocal IOL group.